Trigger-based random access in a multiple bssid network

ABSTRACT

This disclosure provides systems, methods, and apparatuses for operating a wireless station in a multiple basic service set identifier (BSSID) set including a transmitted BSSID (Tx BSSID) and a number of non-transmitted BSSIDs (non-Tx BSSIDs). In some implementations, the wireless station may receive a trigger frame containing a number of association identifier (AID) values based on a group AID mapping contained in a partial virtual bitmap of a traffic indication map (TIM) element, and may determine whether the trigger frame allocates one or more random resource units (RUs) for use by the station based on one or more of the AID values contained in the trigger frame.

CROSS-REFERENCE TO RELATED APPLICATION

This Patent Application claims priority to U.S. Provisional PatentApplication No. 62/486,451 entitled “TRIGGER-BASED RANDOM ACCESS IN AMULTIPLE BSSID NETWORK” filed on Apr. 17, 2017, assigned to the assigneehereof. The disclosure of the prior Application is considered part ofand is incorporated by reference in this Patent Application.

TECHNICAL FIELD

This disclosure relates generally to wireless networks, and specificallyto allocating resource units in wireless networks.

DESCRIPTION OF THE RELATED TECHNOLOGY

A wireless local area network (WLAN) may be formed by one or more accesspoints (APs) that provide a shared wireless medium for use by a numberof client devices or stations (STAs). Each AP, which may correspond to aBasic Service Set (BSS), may periodically broadcast beacon frames toenable any STAs within wireless range of the AP to establish andmaintain a communication link with the WLAN. WLANs that operate inaccordance with the IEEE 802.11 family of standards are commonlyreferred to as Wi-Fi networks.

An AP may create and operate multiple BSSs at the same time, and mayassign (or associate) a number of wireless devices to each of the BSSs.Each of the multiple BSSs may operate independently of each other andyet use the same AP. Because different BSSs may include differentnumbers of wireless devices, may have different security parameters andaccess privileges, and may include different types of wireless devices(such as IoT devices, Wi-Fi devices, and so on), it may be desirable forthe AP to prioritize the allocation of resources between multiple BSSs.

SUMMARY

The systems, methods and devices of this disclosure each have severalinnovative aspects, no single one of which is solely responsible for thedesirable attributes disclosed herein.

One innovative aspect of the subject matter described in this disclosurecan be used as a method of operating wireless stations in a multiplebasic service set identifier (BSSID) set including a transmitted BSSID(Tx BSSID) and a number of non-transmitted BSSIDs (non-Tx BSSIDs). Insome implementations, the method may be performed by a wireless stationand may include receiving a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in a partial virtual bitmap of a traffic indication map (TIM)element, and determining whether the trigger frame allocates one or morerandom resource units (RUs) for use by the station based on one or moreof the AID values contained in the trigger frame. In someimplementations, the one or more random RUs may be allocated for atleast one of a group of stations, a specific BSSID, a group of BSSIDs,and all of the stations belonging to the multiple BSSID set. In someaspects, one of the AID values contained in the trigger frame may be setto a special value that allocates one or more random RUs to all stationsbelonging to the multiple BSSID set.

When the trigger frame is received from an access point (AP)corresponding to the Tx BSSID, its transmitter address (TA) may be setto a MAC address of the Tx BSSID. When the station is associated withthe Tx BSSID, the wireless station may determine whether one or morerandom RUs are allocated for use by the wireless station by identifying,in the trigger frame, an AID value set to zero. When the station isassociated with a respective one of the non-Tx BSSIDs, the wirelessstation may determine whether one or more random RUs are allocated foruse by the wireless station by identifying, in the trigger frame, an AIDvalue set to a BSSID index of the respective non-Tx BSSID. When thestation is not associated with any of the BSSIDs, the wireless stationmay determine whether one or more random RUs are allocated for use bythe wireless station by identifying, in the trigger frame, an AID valueset to a BSSID index of the respective non-Tx BSSID.

When the trigger frame is received from an AP corresponding to arespective one of the non-Tx BSSIDs, its transmitter address (TA) may beset to a MAC address of the respective non-Tx BSSID. When the station isassociated with the respective non-Tx BSSIDs, the wireless station maydetermine whether one or more random RUs are allocated for use by thewireless station by identifying, in the trigger frame, an AID value setto zero. When the station is not associated with any of the BSSIDs, thewireless station may determine whether one or more random RUs areallocated for use by the wireless station by identifying, in the triggerframe, an AID value set to 2045.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in a wireless station belonging to amultiple basic service set identifier (BSSID) set including atransmitted BSSID (Tx BSSID) and a number of non-transmitted BSSIDs(non-Tx BSSIDs). In some implementations, the wireless station mayinclude one or more processors and a memory. The memory can storeinstructions that, when executed by the one or more processors, causethe wireless station to receive a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in a partial virtual bitmap of a traffic indication map (TIM)element, and to determine whether the trigger frame allocates one ormore random resource units (RUs) for use by the station based on one ormore of the AID values contained in the trigger frame.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in a non-transitory computer-readablemedium. The non-transitory computer-readable medium can storeinstructions that, when executed by one or more processors of a wirelessstation belonging to a multiple basic service set identifier (BSSID) setincluding a transmitted BSSID (Tx BSSID) and a number of non-transmittedBSSIDs (non-Tx BSSIDs), causes the wireless station to perform a numberof operations. In some implementations, the number of operations mayinclude receiving a trigger frame containing a number of associationidentifier (AID) values based on a group AID mapping contained in apartial virtual bitmap of a traffic indication map (TIM) element, anddetermining whether the trigger frame allocates one or more randomresource units (RUs) for use by the station based on one or more of theAID values contained in the trigger frame.

Another innovative aspect of the subject matter described in thisdisclosure can be implemented in a wireless station belonging to amultiple basic service set identifier (BSSID) set including atransmitted BSSID (Tx BSSID) and a number of non-transmitted BSSIDs(non-Tx BSSIDs). In some implementations, the wireless station mayinclude means for receiving a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in a partial virtual bitmap of a traffic indication map (TIM)element, and means for determining whether the trigger frame allocatesone or more random resource units (RUs) for use by the station based onone or more of the AID values contained in the trigger frame.

Details of one or more implementations of the subject matter describedin this disclosure are set forth in the accompanying drawings and thedescription below. Other features, aspects, and advantages will becomeapparent from the description, the drawings and the claims. Note thatthe relative dimensions of the following figures may not be drawn toscale.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A shows a block diagram of a wireless system within which aspectsof the present disclosure may be implemented.

FIG. 1B shows a block diagram of another wireless system within whichaspects of the present disclosure may be implemented.

FIG. 2A shows an example multiple Basic Service Set Identification(BSSID) element.

FIG. 2B shows an example non-transmitted Basic Service SetIdentification (BSSID) capabilities element.

FIG. 2C shows an example multiple BSSID-index element.

FIG. 2D shows an example Flexible Multicast Service (FMS) descriptorelement.

FIG. 2E shows an example partial virtual bitmap field.

FIG. 3 shows a block diagram of an example wireless station.

FIG. 4 shows a block diagram of an example access point.

FIG. 5A shows an example subcarrier allocation diagram for a 20 MHzbandwidth.

FIG. 5B shows an example subcarrier allocation diagram for a 40 MHzbandwidth.

FIG. 5C shows an example subcarrier allocation diagram for an 80 MHzbandwidth.

FIG. 6A shows a sequence diagram depicting an example allocation ofdedicated resource units (RUs) to a number of wireless stations.

FIG. 6B shows a sequence diagram depicting an example allocation ofrandom RUs to a number of wireless stations.

FIG. 7 shows a sequence diagram depicting an example allocation ofrandom RUs to a selected Basic Service Set (BSS).

FIG. 8 shows a sequence diagram depicting an example allocation ofdedicated RUs and random RUs to a number of STAs belonging to a multipleBSSID set.

FIG. 9 shows an example trigger frame.

FIG. 10A shows an example Common Info field.

FIG. 10B shows an example Per User Info field.

FIG. 10C shows an example Random Access Parameter Set (RAPS) element.

FIG. 11A shows an illustrative flow chart depicting an example operationfor allocating wireless resources to a multiple basic service setidentifier (BSSID) set.

FIG. 11B shows an illustrative flow chart depicting an example operationfor allocating random resource units (RUs) in a trigger frametransmitted from a transmitted BSSID.

FIG. 11C shows an illustrative flow chart depicting an example operationfor allocating random resource units (RUs) in a trigger frametransmitted from a non-transmitted BSSID.

FIG. 12 shows an illustrative flow chart depicting another exampleoperation for allocating wireless resources of a multiple BSSID set to anumber of stations.

FIG. 13 shows an illustrative flow chart depicting an example operationfor operating a wireless station in a multiple basic service setidentifier (BSSID) set.

Like reference numerals refer to corresponding parts throughout thedrawing figures.

DETAILED DESCRIPTION

The following description is directed to certain implementations for thepurposes of describing the innovative aspects of this disclosure.However, a person having ordinary skill in the art will readilyrecognize that the teachings herein can be applied in a multitude ofdifferent ways. The described implementations may be implemented in anydevice, system or network that is capable of transmitting and receivingRF signals according to any of the IEEE 16.11 standards, or any of theIEEE 802.11 standards, the Bluetooth® standard, code division multipleaccess (CDMA), frequency division multiple access (FDMA), time divisionmultiple access (TDMA), Global System for Mobile communications (GSM),GSM/General Packet Radio Service (GPRS), Enhanced Data GSM Environment(EDGE), Terrestrial Trunked Radio (TETRA), Wideband-CDMA (W-CDMA),Evolution Data Optimized (EV-DO), 1xEV-DO, EV-DO Rev A, EV-DO Rev B,High Speed Packet Access (HSPA), High Speed Downlink Packet Access(HSDPA), High Speed Uplink Packet Access (HSUPA), Evolved High SpeedPacket Access (HSPA+), Long Term Evolution (LTE), AMPS, or other knownsignals that are used to communicate within a wireless, cellular orinternet of things (IOT) network, such as a system utilizing 3G, 4G or5G, or further implementations thereof, technology.

A multiple basic service set identification (BSSID) set may include aplurality of basic service set (BSSs) each associated with or operatedby a corresponding access point (AP) or virtual access point. All APsbelonging to a multiple BSSID set all use a common operating class, acommon channel, a common channel access mechanism, and a common antennaconnector. Further, the BSSIDs assigned to the APs belonging to themultiple BSSID share the same 48-n MSBs, and the BSSIDs assigned to theAPs are not available as MAC addresses for stations using a differentoperating class, channel or antenna connector. In a multiple BSSID set,one of the APs and its associated BSS may be designated as thetransmitted BSSID (or the “Tx BSSID”), and the other APs and theirassociated BSSs may be designated as “non-transmitted BSSIDs” (or the“non-Tx BSSIDs”). Thus, the terms “transmitted BSSID” and “Tx BSSID” maybe used interchangeably herein, and the terms “non-transmitted BSSID”and “non-Tx BSSID” may be used interchangeably herein.

Implementations of the subject matter described in this disclosure maybe used for operating a wireless station in a multiple basic service setidentifier (BSSID) set. The multiple BSSID set may include a transmittedBSSID (Tx BSSID) and a number of non-transmitted BSSIDs (non-Tx BSSIDs).In some implementations, the wireless station may receive a managementframe including a partial virtual bitmap and a number of random accessparameter set (RAPS) elements. Each RAPS element may indicate orthogonalfrequency-division multiple access (OFDMA) contention window values forstations associated with a corresponding one of the BSSIDs. In someimplementations, the management frame is transmitted by the Tx BSSID andincludes a RAPS element for the Tx BSSID. If the wireless stationbelongs to a respective one of the non-Tx BSSIDs and has not received aRAPS element corresponding to the respective non-Tx BSSID, the wirelessstation may inherit the RAPS element of the Tx BSSID based on theabsence of any RAPS element corresponding to the respective non-TxBSSID. In other implementations, the respective non-Tx BSSID may notallocate random RUs to its associated stations. In some aspects, therespective non-Tx BSSID may advertise a RAPS element that includes aspecial value or a dedicated field explicitly indicating that therespective non-Tx BSSID does not allocate random RUs. In other aspects,the RAPS element may include a length field set to one or may be missingan 01-DMA contention window (OCW) range field to indicate that therespective non-Tx BSSID does not allocate random RUs.

The wireless station may receive a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in the partial virtual bitmap of a traffic indication map(TIM) element, and may determine whether the trigger frame allocates oneor more random resource units (RUs) for use by the station based on oneor more of the AID values contained in the trigger frame. When thetrigger frame is received from an AP corresponding to the Tx BSSID andthe wireless station is associated with the Tx BSSID, the wirelessstation may determine whether the trigger frame allocates one or morerandom RUs for use by the station by identifying, in the trigger frame,an AID value set to zero. When the trigger frame is received from an APcorresponding to the Tx BSSID and the wireless station is associatedwith respective one of the non-Tx BSSIDs, the wireless station maydetermine whether the trigger frame allocates one or more random RUs foruse by the station by identifying, in the trigger frame, an AID valueset to a BSSID index of the respective non-Tx BSSID. When the wirelessstation is not associated with any of the BSSIDs, the wireless stationmay determine whether the trigger frame allocates one or more random RUsfor use by the station by identifying, in the trigger frame, an AIDvalue set to 2045.

When the trigger frame is received from an AP corresponding to arespective one of the non-Tx BSSIDs and the station wireless station isassociated with the respective non-Tx BSSID, the wireless station maydetermine whether the trigger frame allocates one or more random RUs foruse by the station by identifying, in the trigger frame, an AID valueset to zero. When the trigger frame is received from an AP correspondingto a respective one of the non-Tx BSSIDs and the wireless station is notassociated with any of the BSSIDs, the wireless station may determinewhether the trigger frame allocates one or more random RUs for use bythe station by identifying, in the trigger frame, an AID value set to2045.

As used herein, the term “associated STA” refers to a STA that isassociated with a given AP, and the term “non-associated STA” refers toa STA that is not associated with the given AP. In addition, as usedherein, the term “directed trigger frame” may refer to a trigger framethat directs each of a number of STAs identified in the trigger frame totransmit uplink (UL) multi-user (MU) data on a resource unit allocatedto the STA, and the term “random trigger frame” may refer to a triggerframe that allows any receiving STA to transmit UL MU data on one ormore shared resource units indicated in the trigger frame. Further, aRandom Access Parameter Set (RAPS) element may also be referred to as ULOFDMA-based Random Access (UORA) Parameter Set element. Thus, the termsRAPS element and UORA Parameter Set element may be used interchangeablyherein.

FIG. 1A is a block diagram of a wireless system 100 within which aspectsof the present disclosure may be implemented. The wireless system 100 isshown to include four wireless stations STA1-STA4, a wireless accesspoint (AP) 110, and a wireless local area network (WLAN) 120. The WLAN120 may be formed by a plurality of Wi-Fi access points (APs) that mayoperate according to the IEEE 802.11 family of standards (or accordingto other suitable wireless protocols). Thus, although only one AP 110 isshown in FIG. 1A for simplicity, it is to be understood that WLAN 120may be formed by any number of access points such as AP 110. The AP 110may be assigned a unique media access control (MAC) address that isprogrammed therein by, for example, the manufacturer of the accesspoint. Similarly, each of stations STA1-STA4 may also be assigned aunique MAC address. In some aspects, the AP 110 may assign anassociation identification (AID) value to each of the stationsSTA1-STA4, for example, so that the AP 110 may identify the stationsSTA1-STA4 using their assigned AID values.

In some implementations, the WLAN 120 may allow for multiple-inputmultiple-output (MIMO) communications between the AP 110 and thestations STA1-STA4. The MIMO communications may include single-user MIMO(SU-MIMO) and multi-user MIMO (MU-MIMO) communications. In some aspects,the WLAN 120 may utilize a multiple channel access mechanism such as,for example, an orthogonal frequency-division multiple access (OFDMA)mechanism. Although the WLAN 120 is depicted in FIG. 1A as aninfrastructure basic service set (BSS), in other implementations, theWLAN 120 may be an independent basic service set (IBSS), an ad-hocnetwork, or a peer-to-peer (P2P) network (such as operating according tothe Wi-Fi Direct protocols).

Each of the stations STA1-STA4 may be any suitable wireless deviceincluding, for example, a cell phone, personal digital assistant (PDA),tablet device, laptop computer, or the like. Each of the stationsSTA1-STA4 may also be referred to as a user equipment (UE), a subscriberstation, a mobile unit, a subscriber unit, a wireless unit, a remoteunit, a mobile device, a wireless device, a wireless communicationsdevice, a remote device, a mobile subscriber station, an accessterminal, a mobile terminal, a wireless terminal, a remote terminal, ahandset, a user agent, a mobile client, a client, or some other suitableterminology. In some implementations, each of the stations STA1-STA4 mayinclude one or more transceivers, one or more processing resources, oneor more memory resources, and a power source (such as a battery). Thememory resources may include a non-transitory computer-readable medium(such as one or more nonvolatile memory elements, such as EPROM, EEPROM,Flash memory, a hard drive, etc.) that stores instructions forperforming operations described below with respect to FIGS. 7-8 and11-13.

The AP 110 may be any suitable device that allows one or more wirelessdevices to connect to a network (such as a local area network (LAN),wide area network (WAN), metropolitan area network (MAN), or theInternet) via the AP 110 using wireless communications such as, forexample, Wi-Fi, Bluetooth, and cellular communications. In someimplementations, the AP 110 may include one or more transceivers, one ormore processing resources, one or more memory resources, and a powersource. The memory resources may include a non-transitorycomputer-readable medium (such as one or more nonvolatile memoryelements, such as EPROM, EEPROM, Flash memory, a hard drive, etc.) thatstores instructions for performing operations described below withrespect to FIGS. 7-8 and 11-13.

For the stations STA1-STA4 and the AP 110, the one or more transceiversmay include Wi-Fi transceivers, Bluetooth transceivers, cellulartransceivers, and any other suitable radio frequency (RF) transceivers(not shown for simplicity) to transmit and receive wirelesscommunication signals. Each transceiver may communicate with otherwireless devices in distinct operating frequency bands, using distinctcommunication protocols, or both. For example, the Wi-Fi transceiver maycommunicate within a 900 MHz frequency band, a 2.4 GHz frequency band, a5 GHz frequency band, and a 60 MHz frequency band in accordance with theIEEE 802.11 standards. The Bluetooth transceiver may communicate withinthe 2.4 GHz frequency band in accordance with the standards provided bythe Bluetooth Special Interest Group (SIG), in accordance with the IEEE802.15 standards, or both. The cellular transceiver may communicatewithin various RF frequency bands in accordance with any suitablecellular communications standard.

FIG. 1B is a block diagram of an example multiple BSSID set 130 withinwhich aspects of the present disclosure may be implemented. The multipleBSSID set 130 includes a plurality of basic service sets BSS0-BSSk, eachassociated with or operated by a corresponding access point 140 (orvirtual access point) such as, for example, the AP 140. An AP mayannounce the existence of the multiple BSSID set 130 and identify theindividual basic service sets BSS0-BSSk that belong to the multipleBSSID set 130 in a single management frame (such as a beacon frame or aprobe response frame). In some implementations, the management frame mayinclude a Multiple BSSID element to announce a multiple BSSID capabilityof the AP and the existence of multiple basic service sets (BSSs)operated or controlled by the AP. The multiple BSSID capability mayindicate an ability to advertise information for multiple BSSIDs using asingle beacon frame or a single probe response frame (rather than usingmultiple beacon frames or multiple probe response frames). In someimplementations, the multiple BSSID capability may indicate the abilityto use a single traffic indication map (TIM) element to indicate apresence of group address traffic for delivery to any of the basicservice sets BSS0-BSSk belonging to the multiple BSSID set 130 and toindicate the presence of queued downlink (DL) data for one or moreindividual STAs regardless of which of the basic service sets BSS0-BSSkthe individual STAs are associated with.

Each STA that receives the Multiple BSSID element may respond to the APand indicate whether the STA is capable of supporting multiple BSSs. Insome implementations, if a STA supports Multiple BSSID capabilities,then the STA can assert a corresponding bit in an Extended CapabilitiesIE that is transmitted to the AP in a frame or packet. In some aspects,the STA may provide the Extended Capabilities IE in a probe request(such as during active scanning operations). In other aspects, the STAmay provide the Extended Capabilities IE in an association request (suchas during passive scanning operations). If multiple BSSID capabilitiesare supported, then the AP may transmit beacon frames using any basictransmission rate that is supported by all of the BSSs associated withor controlled by the AP.

Each of the basic service sets BSS0-BSSk may be assigned a differentBSSID index, for example, so that the AP and each of the sets ofwireless stations STAs can distinguish between data transmissionscorresponding to each of the different basic service sets BSS0-BSSk. Insome implementations, the BSSID index assigned to each of the basicservice sets BSS0-BSSk may be a unique identifier (such as a unique48-bit identifier). In some aspects, the BSSID indices may be used asfiltering addresses, for example, so that only the wireless stationsSTAs associated with a given BSS may receive and decode frames orpackets intended for reception by wireless devices belonging to orassociated with the given BSS.

For purposes of discussion herein, the basic service set BSS0 isdesignated as the Tx BSSID, and may transmit management framescontaining the Multiple BSSID element. The other basic service setsBSS1-BSSk are designated as the non-Tx BSSIDs, and do not transmitmanagement frames containing the Multiple BSSID element. In someimplementations, the Tx BSSID is assigned a BSSID index=0, and may beused as a reference index upon which the BSSID indices of the non-TxBSSIDs are based. For example, the basic service set BSS1 may beassigned a BSSID index=1, the basic service set BSS2 may be BSSIDindex=2, the basic service set BSS3 may be assigned a BSSID index=3, andso on, and the basic service set BSSk may be assigned a BSSID index=k.Using a range of index values between 0 and k to identify each of theBSSIDs in the multiple BSSID set 130 may allow a TIM element in amanagement frame to indicate a presence of group address traffic foreach of the BSSIDs in the multiple BSSID set 130, as described in moredetail below with respect to FIG. 2E.

For the example multiple BSSID set 130 of FIG. 1B, the Tx BSSID(corresponding to the basic service set BSS0) is shown to includeassociated stations STA1-STA9, the first non-Tx BSSID (corresponding tothe basic service set BSS1) is shown to include associated stationsSTA10-STA50, the second non-Tx BSSID (corresponding to the basic serviceset BSS2) is shown to include associated stations STA51-STA55, the thirdnon-Tx BSSID (corresponding to the basic service set BSS3) is shown toinclude associated stations STA60-STA70, and so on, where the k^(th)non-Tx BSSID (corresponding to the basic service set BSSk) is shown toinclude associated stations STA90-STA99. In other exampleimplementations, each of the basic service sets BSS0-BSSk may includeother suitable numbers of stations.

An AP (such as the AP 140) may assign a unique AID value to each of thestations STA1-STA99 belonging to the multiple BSSID set 130, forexample, so that each of the stations STA1-STA99 can be individuallyidentified and addressed by TIM elements that indicate a presence ofbuffered downlink (DL) data and by trigger frames that allocate resourceunits (RUs) for the transmission of uplink (UL) data. In someimplementations, a certain number of AID values may be reserved forindicating the presence of group address traffic for the BSSIDs in themultiple BSSID set 130, and may not be assigned to any of the stationsSTA1-STA99.

A trigger frame may contain one or more User Info fields (UIFs). In someimplementations, a trigger frame transmitted by an AP may includemultiple UIFs. Each of the UIFs may assign a resource unit (RU) uponwhich a recipient STA can use to transmit uplink (UL) traffic to the AP.In some implementations, each UIF may include an AID12 subfield thatcontains the AID of the STA to which a corresponding RU is allocated. Insome aspects, only the STA identified by the AID value in the UIF maytransmit UL data on the allocated RU (hereinafter denoted as a dedicatedRU). In addition, or in the alternative, the AID in a UIF of a triggerframe may be set to a special value that allows the allocated RUs to beshared by multiple STAs. These shared RUs may be referred to as randomRUs. For one example, the AID may be set to zero (0) to allocate randomRUs to a group of associated STAs that have not been allocated anydedicated RUs. For another example, the AID may be set to the value 2045to allocate random RUs to all unassociated STAs.

As depicted in the example of FIG. 1B, the AP 140 may operate the basicservice sets BSS1-BSSk associated with the non-Tx BSSIDs using acorresponding number of virtual access points VAP1-VAPk. Each of thevirtual access points VAP1-VAPk may manage a corresponding one of thebasic service sets BSS1-BSSk, respectively, and may operate in a mannersimilar to a stand-alone access point. Although the virtual accesspoints VAP1-VAPk may be physically contained or integrated within asingle access point or device (such as the AP 140), each of the virtualaccess points VAP1-VAPk may use (or be assigned) a different transmitteraddress (TA) when transmitting frames to STAs belonging to acorresponding one of the BSSs, and may use (or be assigned) a differentreceiver address (RA) when receiving frames from STAs belonging to acorresponding one of the BSSs. In this manner, the various stationsSTA1-STA99 belonging to the multiple BSSID set 130 can distinguishbetween the Tx BSSID and the non-Tx BSSIDs corresponding to thedifferent basic service sets BSS0-BSSk, respectively, when transmittingand receiving data. Assigning a different TA and a different RA to eachof the virtual access points VAP1-VAPk may also allow a new station(such as a station not yet associated with any AP) to identify theexistence of the multiple BSSID set 130 and to identify each of thebasic service sets BSS0-BSSk that belong to the multiple BSSID set 130.

The Multiple BSSID element also may allow an AP to indicate the presenceof group address traffic for the Tx BSSID, to indicate the presence ofgroup address traffic for each of the non-Tx BSSIDs, and to indicate thepresence of queued downlink (DL) data for STAs associated with any ofthe different BSSs belonging to the multiple BSSID set 130 (irrespectiveof whether the STAs are associated with the Tx BSSID or one of thenon-Tx BSSIDs) using a single traffic indication map (TIM) element. TheTIM element may be transmitted in a single management frame (such as abeacon frame or a probe response frame). In some implementations,mappings between bits contained in a partial virtual bitmap included inthe TIM element and AID values corresponding to the stations STA1-STA99and the BSSIDs in the multiple BSSID set 130 may be used by triggerframes disclosed herein to allocate not only dedicated resource units(RUs) to the stations STA1-STA99 in the multiple BSSID set 130 but alsorandom RUs to one or more specific BBSIDs in the multiple BSSID set. Theallocation of dedicated RUs and/or random RUs in trigger frames isdescribed in more detail below with respect to FIGS. 8 and 11-12.

FIG. 2A shows an example Multiple BSSID element 200. The Multiple BSSIDelement 200, which may be used by an AP to indicate that the AP belongsto a Multiple BSSID set (such as the multiple BSSID set 130 includingthe basic service sets BSS0-BSSk of FIG. 1B), is shown to include anelement ID field 201, a length field 202, a MaxBSSID Indicator field203, and an optional Sub-elements field 204. The element ID field 201may store a value indicating the element type (such as a Multiple BSSIDelement). The length field 202 may store a value indicating a length ofthe Multiple BSSID element 200. The MaxBSSID Indicator field 203 maystore a value indicating the maximum possible number of BSSIDs in themultiple BSSID set. In some aspects, the actual number of BSSIDs in themultiple BSSID set may not be explicitly signaled. The MaxBSSIDIndicator field 203 may store a value of “n” to indicate a maximumnumber 2^(n) of BSSIDs supported by the AP. In some aspects, amanagement frame (such as a beacon frame or a probe response frame) mayinclude more than one Multiple BSSID element 210.

In some implementations, the BSSID index of the Tx BSSID may bedesignated as the reference BSSID index, and the BSSID indices of theother non-Tx BSSIDs may be based on (or indexed relative to) thereference BSSID index. In some aspects, the BSSID(i) index correspondingto the i^(th) BSSID in the multiple BSSID set may be derived from thereference BSSID (BSSID_REF) index as shown below:

BSSID(i)=BSSID_A|BSSID_B,

where BSSID_A is a BSSID index with (48-n) MSBs equal to the (48-n) MSBsof the reference BSSID index and n LSBs equal to 0; BSSID_B is a BSSIDindex with (48-n) MSBs equal to 0 and n LSBs equal to [(n LSBs ofREF_BSSID)+i] mod 2^(n). In these implementations, when the MultipleBSSID element 200 is transmitted in a beacon frame or in a proberesponse frame, the BSSID index of the frame is set to the referenceBSSID index (such as the BSSID index of the AP that transmitted thebeacon frame).

The optional Sub-elements field 204 may store zero or more additionalsub-elements. For the example of FIG. 2A, the Sub-elements field 204 isshown to include a non-Tx BSSID profile 205. The non-Tx BSSID profile205 may contain a list of elements for one or more APs (or virtual APs)associated with the non-Tx BSSIDs. In some aspects, the non-Tx BSSIDprofile 205 may contain at least a non-Tx BSSID capabilities element210, an SSID and BSSID-index element 220, and an FMS descriptor element230. The non-Tx BSSID capabilities element 210, the SSID and BSSID-indexelement 220, and the FMS descriptor element 230 are described below withrespect to FIGS. 2B, 2C, and 2D, respectively.

FIG. 2B shows an example non-Tx BSSID capabilities element 210. Thenon-Tx BSSID capabilities element 210 may be used by the Tx BSSID toadvertise its support of multiple BSSs (such as the basic service setsBSS0-BSSk). In some implementations, the non-Tx BSSID capabilitieselement 210 may be included in all beacon frames broadcast by the TxBSSID. In other implementations, the non-Tx BSSID capabilities element210 may be included in selected beacon frames broadcast by the Tx BSSID.The non-Tx BSSID capabilities element 210 is shown to include an elementID field 211, a length field 212, a non-Tx BSSID capability field 213, aDirectional Multi-Gigabit (DMG) BSS control field 214, and a non-TxBSSID DMG capabilities field 215. The element ID field 211 may store avalue indicating the element type (such as a non-Tx BSSID capabilitieselement). The length field 212 may store a value indicating a length ofthe Multiple BSSID capability element 200.

The non-Tx BSSID Capability field 213 includes the contents of theCapability Information field in beacons for the BSS when transmitted bya non-DMG STA. The DMG BSS Control field 214 and the non-Tx BSSID DMGCapabilities Element 215 may not be present when the transmitting deviceis a non-DMG STA.

FIG. 2C shows an example Multiple BSSID-index element 220. The MultipleBSSID-index element 220, which may be included in the Multiple BSSIDelement and used by the Tx BSSID to identify a corresponding non-TxBSSID and its DTIM parameters, is shown to include an element ID field221, a length field 222, a BSSID index 223, an optional delayed trafficindication map (DTIM) period 224, and an optional DTIM count 225. Theelement ID field 221 may store a value indicating the element type (suchas a Multiple BSSID-index element). The length field 222 may store avalue indicating a length of the Multiple BSSID-index IE 220. The BSSIDIndex field 223 may store a value between 1 and 2^(n)−1 that identifiesthe corresponding non-Tx BSSID, where n is a nonzero, positive integervalue indicating the number of bits in the BSSID index (and 2^(n)indicates the maximum number of supported BSSIDs). In some aspects, oneor more of the index values may not be active, in which case themultiple BSSID-Index element 220 may indicate which of the index valuesare active. The DTIM period field 224 indicates the DTIM period for theBSSID, for example, by storing a value indicating how many beaconintervals occur between DTIM beacon frame transmissions. The DTIM countfield 225 indicates the number of beacon intervals remaining until thenext DTIM beacon frame is broadcast for the BSSID.

In some implementations, the Multiple BSSID-index element 220 mayinclude both the DTIM Period field 224 and the DTIM count field 225 whentransmitted in a beacon frame, and the Multiple BSSID-index element 220may not include either the DTIM Period field 224 or the DTIM count field225 when transmitted in a probe response frame. In otherimplementations, the Multiple BSSID-index element 220 may include eitherthe DTIM Period field 224 or the DTIM count field 225 when transmittedin a probe response frame.

In some implementations, the SSID may be provided in all beacon frames,while the FMS Descriptor element may be provided in selected beaconframes based, for example, on whether the beacon frame's TIM elementindicates the presence of queued DL data for STAs that are associatedwith one or more of the non-Tx BSSIDs. In some aspects, the FMSDescriptor element may be included in the non-Tx BSSID Profilesubelement of a particular beacon frame if the beacon frame's TIM fieldindicates a presence of buffered group-addressed frames for thecorresponding non-Tx BSSID. Conversely, the FMS Descriptor element maynot be included in the non-Tx BSSID Profile subelement of a particularbeacon frame if the beacon frame's TIM field does not indicate apresence of buffered group-addressed frames for the corresponding non-TxBSSID.

FIG. 2D shows an example FMS descriptor element 230. The FMS descriptorelement 230 may be used by the AP 110 to provide information about groupaddressed frames buffered in the Tx BSSID. The FMS descriptor element230 may be included within beacon frames broadcast from the Tx BSSID. Insome implementations, the FMS descriptor element 230 can be included inthe non-Tx BSSID Profile subelement if the Multiple BSSID element isincluded in a beacon frame and if the TIM field indicates there arebuffered group addressed frames for the non-Tx BSSID.

The FMS descriptor element 230 is shown to include an element ID field231, a length field 232, a number of FSM counters field 233, an FMScounters field 234, and an FSMIDs field 235. The element ID field 231may store a value indicating the element type (such as a FMS descriptorelement). The length field 232 may store a value indicating a length ofthe FMS descriptor element 230. If no FMS streams are accepted by the TxBSSID, then the length may be set to zero. Otherwise, the length may beset to a value=1+m+n, where “n” is an integer indicating the number ofFMS counters and “m” is an integer indicating the number of FMSIDspresent in the FMS descriptor IE 230. The number of FSM counters field233 may store a value indicating the number of FMS counters contained inthe FMS descriptor IE 230. A presence of the FSMIDs field 235 in the FMSdescriptor element 230 may indicate that the Tx BSSID has buffereddownlink data scheduled for delivery to the addressed group immediatelyafter transmission of the next DTIM beacon frame.

In some implementations, the Tx BSSID may provide a partial list ofnon-Tx BSSID profiles in beacon frames when advertising non-Tx BSSIDprofiles. In other implementations, the Tx BSSID may provide differentsets of non-Tx BSSID profiles in different beacon frames whenadvertising non-Tx BSSID profiles. Similarly, in some implementations,the Tx BSSID may provide a partial list of non-Tx BSSID profiles inprobe response frames, and in other implementations may providedifferent sets of non-Tx BSSID profiles in different probe responseframes. In some aspects, a STA may receive all of the BSSID profilesfrom previously received beacon frames (or probe response frames). Inother aspects, a STA may obtain all of the BSSID profiles bytransmitting a probe request frame to the AP associated with Tx BSSID,which in turn may provide the BSSID profiles to the STA in one or moreprobe response frames.

FIG. 2E shows a portion 240 of a TIM element including an example bitmapcontrol field 241 and an example partial virtual bitmap 242. In someimplementations, the portion 240 includes a number of octets of thetraffic indication virtual bitmap of the TIM element of a managementframe transmitted from a Tx BSSID. The maximum possible number ofsupported BSSIDs may be denoted as 2^(n), and an integer “k” mayindicate the number of non-Tx BSSIDs supported by the AP, wherek≤(2^(n)−1). The group AID mapping (which may also be referred to as thegroup-address AID mapping) in the TIM element of a management frame maybe referenced to (or indexed from) the AP that transmitted the beaconframe. In some implementations, the group AID mapping in the TIM elementmay also be used in trigger frames to allocate dedicated RUs to specificSTAs and/or random RUs to individual basic service sets (such as one ormore selected BSSIDs belonging to a multiple BSSID set), as described inmore detail below with respect to FIGS. 8 and 11-12.

For the example of FIG. 2E, the bitmap control field 241 includes2^(n)=2³=8 bits (denoted by bit positions B0-B7), and may be used for amultiple BSSID set including up to eight BSSIDs. Bit B0 of the bitmapcontrol field 241 contains the traffic indication virtual bitmap bitassociated with the Tx BSSID, and the remaining 7 bits of the bitmapcontrol field 241 form the bitmap offset. The bitmap offset may be usedto identify the BSSID index assigned to each of the non-Tx BSSIDsrelative to the BSSID index of the Tx BSSID. For example, the Tx BSSIDmay be assigned a BSSID index=0, a first non-Tx BSSID may be assigned aBSSID index=1, a second non-Tx BSSID may be assigned a BSSID index=2,and so on. In some aspects, bits B0-B7 of the bitmap control field 241correspond to AID values 0 through 8, respectively, such that the TxBSSID may be identified by an AID=0, the first non-Tx BSSID may beidentified by an AID=1, the second non-Tx BSSID may be identified by anAID=2, and so on. In this manner, the bitmap control field 241 mayprovide a mapping between BSSID index values and AID values. Further,because AID values 0 through 7 are assigned to the eight BSSIDs in themultiple BSSID set, an AID=9 is the lowest possible AID value that canbe assigned to a STA belonging to the multiple BSSID set.

In some implementations, the partial virtual bitmap 242 may be describedas including a BSSID portion 242A and a STA portion 242B. For theexample of FIG. 2E, the BSSID portion 242A includes eight bits (denotedby bit positions B0-B7) that may indicate a presence of group addresstraffic for a corresponding one of the eight supported BSSIDs. In someaspects, bit B0 of the BSSID portion 242A may indicate a presence ofgroup address traffic for stations associated with the Tx BSSID, and thebits B1-B7 may indicate a presence of group address traffic for acorresponding one of the seven non-Tx BSSIDs. More specifically,referring also to the multiple BSSID set 130 of FIG. 1B, bit B0 mayindicate whether the AP corresponding to the Tx BSSID (having a BSSIDindex=0 and AID=0) has queued multicast DL data for its associatedstations, bit B1 may indicate whether the AP (or the virtual AP)corresponding to the non-Tx BSSID having a BSSID index=1 and AID=1 hasqueued multicast DL data for its associated, bit B2 may indicate whetherthe AP (or the virtual AP) corresponding to the non-Tx BSSID having aBSSID index=2 and AID=2 has queued multicast DL data its associatedstations, bit B3 may indicate whether the AP (or the virtual AP)corresponding to the non-Tx BSSID having a BSSID index=3 and AID=3 hasqueued multicast DL data for its associated stations, and so on.

When the DTIM Count field in a management frame has a value equal tozero for a BSS that includes a non-Tx BSSID, and one or more groupaddressed frames are buffered at the AP for the Tx BSSID, bits B1through B7 in the BSSID portion 242A of the partial virtual bitmap 242may each be set to 1 to indicate the presence of queued multicastdownlink (DL) data for each of the corresponding non-Tx BSSIDs. For theexample of FIG. 2E, bit B3 in the BSSID portion 242A (denoted byreference circle 243A) is set to 1 to indicate that the non-Tx BSSIDhaving a BSSID index=3 has queued DL multicast data to be delivered.

For the example of FIG. 2E, the STA portion 242B includes bits beginningat position 2^(n)=8 of the partial virtual bitmap 242 (which alsocorresponds to an AID=8). Each of the bits in the STA portion 242B maybe used to indicate a presence of queued DL data for an individual STAbelonging to the multiple BSSID set. In some implementations, each ofthe bits in the STA portion 242B of the partial virtual bitmap 242 maycorrespond to the AID value assigned to a respective one of the STAsbelonging to the multiple BSSID set, and therefore may be used toindicate a presence of queued DL data for the respective STA, regardlessof whether the respective STA is associated with the Tx BSSID or isassociated with one of the non-Tx BSSIDs. In this manner, the partialvirtual bitmap 242 may be used to indicate a presence of queued DL datafor any one or more STAs belonging to the multiple BSSID set 130.

For the example of FIG. 2E, the partial virtual bitmap 242 indicatesthat the AP has queued DL data for the STA having an AID value=12 (asdenoted by reference circle 243B), has queued DL data for the STA havingan AID value=17 (as denoted by reference circle 243C), has queued DLdata for the STA having an AID value=22 (as denoted by reference circle243D), and has queued DL data for the STA having an AID value=24 (asdenoted by reference circle 243E).

In some implementations, a STA may determine whether any of the APs inthe multiple BSSID set 130 has queued DL data for the STA by examiningonly two bits of a partial virtual bitmap 242 contained in a managementframe: one of the two bits is an AID value in the BSSID portion 242Athat indicates a presence of group address traffic for the BSSIDassociated with the STA, and the other of the two bits is an AID valuein the STA portion 242B that indicates a presence of queued DL data forthe STA in any of the APs belonging to the multiple BSSID set. Forexample, referring also to FIG. 1B, if a STA is associated with thenon-Tx BSSID having a BSSID index=3 and has an assigned AID value=12,then the STA can examine the value stored in bit position B3(corresponding to an AID value and BSSID index=3) in the BSSID portion242A to determine whether its associated AP has group address trafficfor its BSSID, and can examine the value stored in the STA portion 242Bcorresponding to the AID value=12 to determine whether any of the APs(or virtual APs) belonging to the multiple BSSID set 130 has DL data forthe STA.

In this manner, any STA within a multiple BSSID set may be able todetermine whether any of the APs belonging to the multiple BSSID set hasDL data for the STA based on (1) the BSSID index of its associated APand (2) its own AID value.

FIG. 3 shows an example STA 300. In some implementations, the STA 300may be one example of one or more of the wireless stations STA1-STA4 ofFIG. 1A or one or more of the wireless stations STA1-STA99 of FIG. 1B.The STA 300 may include a display 302, input/output (I/O) components304, a physical-layer device (PHY) 310, a medium access controller (MAC)320, a processor 330, a memory 340, and a number of antennas350(1)-350(n). The display 302 may be any suitable display or screenupon which items may be presented to a user (such as for viewing,reading, or watching). In some aspects, the display 302 may be atouch-sensitive display that allows for user interaction with the STA300 and that allows the user to control one or more operations of theSTA 300. The I/O components 304 may be or include any suitablemechanism, interface, or device to receive input (such as commands) fromthe user and to provide output to the user. For example, the I/Ocomponents 304 may include (but are not limited to) a graphical userinterface, keyboard, mouse, microphone, speakers, and so on.

The PHY 310 may include at least a number of transceivers 311 and abaseband processor 312. The transceivers 311 may be coupled to theantennas 350(1)-350(n), either directly or through an antenna selectioncircuit (not shown for simplicity). The transceivers 311 may be used totransmit signals to and receive signals from the AP 110 and other STAs(see also FIGS. 1A and 1B), and may be used to scan the surroundingenvironment to detect and identify nearby access points and other STAs(such as within wireless range of the STA 300). Although not shown inFIG. 3 for simplicity, the transceivers 311 may include any number oftransmit chains to process and transmit signals to other wirelessdevices via the antennas 350(1)-350(n), and may include any number ofreceive chains to process signals received from the antennas350(1)-350(n). In some implementations, the STA 300 may be configuredfor MIMO operations. The MIMO operations may include SU-MIMO operationsand MU-MIMO operations. The STA 300 also may be configured for OFDMAcommunications and other suitable multiple access mechanisms, forexample, as may be provided for in the IEEE 802.11ax standards.

The baseband processor 312 may be used to process signals received fromthe processor 330 or the memory 340 (or both) and to forward theprocessed signals to the transceivers 311 for transmission via one ormore of the antennas 350(1)-350(n), and may be used to process signalsreceived from one or more of the antennas 350(1)-350(n) via thetransceivers 311 and to forward the processed signals to the processor330 or the memory 340 (or both).

The MAC 320 may include at least a number of contention engines 321 andframe formatting circuitry 322. The contention engines 321 may contendfor access to one more shared wireless mediums, and may also storepackets for transmission over the one more shared wireless mediums. TheSTA 300 may include one or more contention engines 321 for each of aplurality of different access categories. In other implementations, thecontention engines 321 may be separate from the MAC 320. For still otherimplementations, the contention engines 321 may be implemented as one ormore software modules (such as stored in memory 340 or stored in memoryprovided within the MAC 320) containing instructions that, when executedby the processor 330, perform the functions of the contention engines321.

The frame formatting circuitry 322 may be used to create and formatframes received from the processor 330 (such as by adding MAC headers toPDUs provided by the processor 330), and may be used to re-format framesreceived from the PHY 310 (such as by stripping MAC headers from framesreceived from the PHY 310). Although the example of FIG. 3 depicts theMAC 320 coupled to the memory 340 via the processor 330, in otherimplementations, the PHY 310, the MAC 320, the processor 330, and thememory 340 may be connected using one or more buses (not shown forsimplicity).

The processor 330 may be any suitable one or more processors capable ofexecuting scripts or instructions of one or more software programsstored in the STA 300 (such as within the memory 340). In someimplementations, the processor 330 may be or include one or moremicroprocessors providing the processor functionality and externalmemory providing at least a portion of machine-readable media. In otherimplementations, the processor 330 may be or include an ApplicationSpecific Integrated Circuit (ASIC) with the processor, the businterface, the user interface, and at least a portion of themachine-readable media integrated into a single chip. In some otherimplementations, the processor 330 may be or include one or more FieldProgrammable Gate Arrays (FPGAs) or Programmable Logic Devices (PLDs).

The memory 340 may include a device database 341 that stores profileinformation for the STA 300 and for a number of other wireless devicessuch as APs and other STAs. The profile information for the STA 300 mayinclude, for example, its MAC address, its assigned AID value, the BSSIDof the basic service set to which the STA 300 belongs, bandwidthcapabilities, supported channel access mechanisms, supported data rates,and so on. The profile information for a particular AP may include, forexample, the AP's BSSID index, an indication that the AP corresponds tothe Tx BSSID or to one of the non-Tx BSSIDs, MAC address, channelinformation, received signal strength indicator (RSSI) values, goodputvalues, channel state information (CSI), supported data rates,connection history with the AP, a trustworthiness value of the AP (suchas indicating a level of confidence about the AP's location, etc.), andany other suitable information pertaining to or describing the operationof the AP.

The memory 340 may also include a non-transitory computer-readablemedium (such as one or more nonvolatile memory elements, such as EPROM,EEPROM, Flash memory, a hard drive, and so on) that may store at leastthe following software (SW) modules:

-   -   a frame exchange software module 342 to facilitate the creation        and exchange of any suitable frames (such as data frames, action        frames, control frames, and management frames) between the STA        300 and other wireless devices, for example, as described below        for one or more operations of FIGS. 7-8 and 11-13;    -   a trigger frame reception software module 343 to receive trigger        frames, to determine whether the trigger frames solicit a        response from the STA 300, to determine whether the trigger        frames allocate any dedicated RUs to the STA 300, and to        determine whether the trigger frames allocate any random RUs        that may be used by the STA 300, for example, as described below        for one or more operations of FIGS. 7-8 and 11-13;    -   a resource unit (RU) decoding software module 344 to determine        which (if any) dedicated RUs are allocated to the STA 300, to        determine which (if any) random RUs are allocated for use by the        STA 300, and to determine the size, location, and other        parameters of any allocated RUs, for example, as described below        for one or more operations of FIGS. 7-8 and 11-13; and    -   a BSSID decoding software module 345 to determine the multiple        BSSID capabilities of one or more APs and to determine whether        one or more APs associated with a multiple BSSID set have queued        DL traffic for the STA 300, for example, as described below for        one or more operations of FIGS. 7-8 and 11-13.        Each software module includes instructions that, when executed        by the processor 330, cause the STA 300 to perform the        corresponding functions. The non-transitory computer-readable        medium of the memory 340 thus includes instructions for        performing all or a portion of the operations described below        with respect to FIGS. 7-8 and 11-13.

The processor 330 may execute the frame exchange software module 342 tofacilitate the creation and exchange of any suitable frames (such asdata frames, action frames, control frames, and management frames)between the STA 300 and other wireless devices. The processor 330 mayexecute the trigger frame reception software module 343 to receivetrigger frames, to determine whether the trigger frames solicit aresponse from the STA 300, to determine whether the trigger framesallocate any dedicated RUs to the STA 300, and to determine whether thetrigger frames allocate any random RUs that may be used by the STA 300.The processor 330 may execute the RU decoding software module 344 todetermine which (if any) dedicated RUs are allocated to the STA 300, todetermine which (if any) random RUs are allocated for use by the STA300, and to determine the size, location, and other parameters of anyallocated RUs. The processor 330 may execute the BSSID decoding softwaremodule 345 to determine the multiple BSSID capabilities of one or moreAPs and to determine whether one or more APs associated with a multipleBSSID set have queued DL traffic for the STA 300. In some aspects, theSTA 300 may determine whether one or more APs have queued DL traffic forthe STA 300 by decoding the partial virtual bitmap field of TIM elementsprovided in beacon frames.

FIG. 4 shows an example AP 400. In some implementations, the AP 400 maybe one example of the AP 110 of FIG. 1A or the AP 140 of FIG. 1B. The AP400 may include a PHY 410, a MAC 420, a processor 430, a virtual APmanagement controller 435, a memory 440, a network interface 450, and anumber of antennas 460(1)-460(n). The PHY 410 may include at least anumber of transceivers 411 and a baseband processor 412. Thetransceivers 411 may be coupled to the antennas 460(1)-460(n), eitherdirectly or through an antenna selection circuit (not shown forsimplicity). The transceivers 411 may be used to communicate wirelesslywith one or more STAs, with one or more other APs, and with othersuitable devices. Although not shown in FIG. 4 for simplicity, thetransceivers 411 may include any number of transmit chains to processand transmit signals to other wireless devices via the antennas460(1)-460(n), and may include any number of receive chains to processsignals received from the antennas 460(1)-460(n). In someimplementations, the AP 400 may be configured for MIMO operations suchas SU-MIMO operations and MU-MIMO operations. The AP 400 also may beconfigured for OFDMA communications and other suitable multiple accessmechanisms, for example, as may be provided for in the IEEE 802.11axstandards.

The baseband processor 412 may be used to process signals received fromthe processor 430 or the memory 440 (or both) and to forward theprocessed signals to the transceivers 411 for transmission via one ormore of the antennas 460(1)-460(n), and may be used to process signalsreceived from one or more of the antennas 460(1)-460(n) via thetransceivers 411 and to forward the processed signals to the processor430 or the memory 440 (or both).

The network interface 450 may be used to communicate with a WLAN server(not shown for simplicity) either directly or via one or moreintervening networks and to transmit signals. The virtual AP managementcontroller 435 may be used to control and coordinate the operations of anumber of virtual APs (such as the virtual access points VAP1-VAPk ofFIG. 1B).

The MAC 420 may include at least a number of contention engines 421 andframe formatting circuitry 422. The contention engines 421 may contendfor access to the shared wireless medium, and may also store packets fortransmission over the shared wireless medium. In some implementations,the AP 400 may include one or more contention engines 421 for each of aplurality of different access categories. In other implementations, thecontention engines 421 may be separate from the MAC 420. For still otherimplementations, the contention engines 421 may be implemented as one ormore software modules (such as stored in the memory 440 or within memoryprovided within the MAC 420) containing instructions that, when executedby the processor 430, perform the functions of the contention engines421.

The frame formatting circuitry 422 may be used to create and formatframes received from the processor 430 (such as by adding MAC headers toPDUs provided by the processor 430), and may be used to re-format framesreceived from the PHY 410 (such as by stripping MAC headers from framesreceived from the PHY 410). Although the example of FIG. 4 depicts theMAC 420 coupled to the memory 440 via the processor 430, in otherimplementations, the PHY 410, the MAC 420, the processor 430, and thememory 440 may be connected using one or more buses (not shown forsimplicity).

The processor 430 may be any suitable one or more processors capable ofexecuting scripts or instructions of one or more software programsstored in the AP 400 (such as within the memory 440). In someimplementations, the processor 430 may be or include one or moremicroprocessors providing the processor functionality and externalmemory providing at least a portion of machine-readable media. In otherimplementations, the processor 430 may be or include an ApplicationSpecific Integrated Circuit (ASIC) with the processor, the businterface, the user interface, and at least a portion of themachine-readable media integrated into a single chip. In some otherimplementations, the processor 430 may be or include one or more FieldProgrammable Gate Arrays (FPGAs) or Programmable Logic Devices (PLDs).

The memory 440 may include a device database 441A that stores profileinformation for a plurality of STAs. The profile information for aparticular STA may include, for example, its MAC address, its assignedAID value, supported data rates, connection history with the AP 400, oneor more RUs allocated to the STA, the BSS with which the STA isassociated, the multiple BSSID set to which the STA belongs, and anyother suitable information pertaining to or describing the operation ofthe STA.

The memory 440 may also include a BSSID mapping table 441B that maystore mapping information between AID values and BSSID indices,information indicating which wireless devices are part of or belong toeach of a number of different BSSs, information relating to ordescribing a multiple BSSID set to which the AP 400 belongs, one or morecharacteristics or parameters of each of the different BSSs, and anyother suitable information pertaining to or describing the operation ofone or more BSSs that may be created by, operated by, or otherwiseassociated with the AP 400. In some aspects, the BSSID mapping table441B also may store information indicating mapping information between anumber of virtual APs and their corresponding BSSIDs.

The memory 440 may also include a non-transitory computer-readablemedium (such as one or more nonvolatile memory elements, such as EPROM,EEPROM, Flash memory, a hard drive, and so on) that may store at leastthe following software (SW) modules:

-   -   a frame exchange software module 442 to facilitate the creation        and exchange of any suitable frames (such as data frames, action        frames, control frames, and management frames) between the AP        400 and other wireless devices, for example, as described below        for one or more operations of FIGS. 7-8 and 11-13;    -   a BSS configuration software module 443 to set-up, configure,        and operate multiple BSSs and to assign a number of wireless        devices to each of the BSSs operated by the AP 400, for example,        as described below for one or more operations of FIGS. 7-8 and        11-13;    -   a virtual AP management software module 444 to manage or        otherwise coordinate the operations of a number of virtual APs        associated with a corresponding number of different BSSs, for        example, as described below for one or more operations of FIGS.        7-8 and 11-13;    -   a resource unit (RU) allocation software module 445 to allocate        a number of dedicated RUs to a number of wireless devices        identified by a trigger frame, to allocate a number of random        RUs to be shared by a number of wireless devices that receive a        trigger frame, and to allocate one or more random RUs to each of        a number of selected basic service sets (such as one or more        selected BSSIDs belonging to a multiple BSSID set), for example,        as described below for one or more operations of FIGS. 7-8 and        11-13; and    -   a trigger frame software module 446 to facilitate the        transmission of trigger frames to one or more wireless devices,        for example, as described below for one or more operations of        FIGS. 7-8 and 11-13.        Each software module includes instructions that, when executed        by the processor 430, cause the AP 400 to perform the        corresponding functions. The non-transitory computer-readable        medium of the memory 440 thus includes instructions for        performing all or a portion of the operations described below        with respect to FIGS. 7-8 and 11-13.

The processor 430 may execute the frame exchange software module 442 tofacilitate the creation and exchange of any suitable frames (such asdata frames, action frames, control frames, and management frames)between the AP 400 and other wireless devices. The processor 430 mayexecute the BSS configuration software module 443 to set-up, configure,and operate multiple BSSs and to assign a number of wireless devices toeach of the BSSs operated by the AP 400. The processor 430 may executethe virtual AP management software module 444 to manage or otherwisecoordinate the operations of a number of virtual APs associated with acorresponding number of different BSSs. In some aspects, execution ofthe virtual AP management software module 444 may be used to coordinatethe allocation of random RUs by the different BSSs based one or moreparameters, for example, that may increase the fairness with which allof the STAs belonging to a multiple BSSID set may contend with eachother for access to the random RUs.

The processor 430 may execute the RU allocation software module 445 toallocate a number of dedicated RUs to a number of wireless devicesidentified by a trigger frame, to allocate a number of random RUs to beshared by a number of wireless devices that receive a trigger frame, andto allocate one or more random RUs to each of a number of selected basicservice sets (such as one or more selected BSSIDs belonging to amultiple BSSID set). The processor 430 may execute the trigger framesoftware module 446 to facilitate the transmission of trigger frames toone or more wireless devices. In some aspects, execution of the triggerframe software module 446 may be used to allocate dedicated RUs to oneor more identified STAs and to allocate random RUs to a selected groupof STAs or to a selected group of BSSs in the same trigger frame.

The IEEE 802.11ax specification may introduce multiple accessmechanisms, such as an orthogonal frequency-division multiple access(OFDMA) mechanism, to allow multiple STAs to transmit and receive dataon a shared wireless medium at the same time. For a wireless networkusing OFDMA, the available frequency spectrum may be divided into aplurality of resource units (RUs) each including a number of differentfrequency subcarriers, and different RUs may be allocated or assigned(such as by an AP) to different wireless devices (such as STAs) at agiven point in time. In this manner, multiple wireless devices mayconcurrently transmit data on the wireless medium using their assignedRUs or frequency subcarriers.

FIG. 5A shows an example subcarrier allocation diagram 500 for a 20 MHzbandwidth according to the IEEE 802.11ax standards. As shown in FIG. 5A,a 20 MHz bandwidth may be divided into a number of resource units (RUs),and each RU may include a number of subcarriers. In some aspects, afirst subcarrier allocation 501 may include a number of RUs eachincluding 26 subcarriers, a second subcarrier allocation 502 may includea number of RUs each including 52 subcarriers, a third subcarrierallocation 503 may include a number of RUs each including 106subcarriers, and a fourth subcarrier allocation 504 may include one RUincluding 242 subcarriers (with the left half of the channel forsingle-user (SU) operations). For each of the example subcarrierallocations 501-504 depicted in FIG. 5A, adjacent RUs may be separatedby a null subcarrier (such as a DC subcarrier), for example, to reduceleakage between adjacent RUs.

FIG. 5B shows an example subcarrier allocation diagram 510 for a 40 MHzbandwidth according to the IEEE 802.11ax standards. As shown in FIG. 5B,a 40 MHz bandwidth may be divided into a number of RUs, and each RU mayinclude a number of subcarriers. In some aspects, a first subcarrierallocation 511 may include a number of RUs each including 26subcarriers, a second subcarrier allocation 512 may include a number ofRUs each including 52 subcarriers, a third subcarrier allocation 513 mayinclude a number of RUs each including 106 subcarriers, a fourthsubcarrier allocation 514 may include a number of RUs each including 242subcarriers, and a fifth subcarrier allocation 515 may include one RUincluding 484 subcarriers (with the left half of the channel for SUoperations). For each of the example subcarrier allocations 511-515depicted in FIG. 5B, adjacent RUs may be separated by a null subcarrier,for example, to reduce leakage between adjacent RUs.

FIG. 5C shows an example subcarrier allocation diagram 520 for an 80 MHzbandwidth according to the IEEE 802.11ax standards. As shown in FIG. 5C,an 80 MHz bandwidth may be divided into a number of resource units(RUs), and each RU may include a number of subcarriers. In some aspects,a first subcarrier allocation 521 may include a number of RUs eachincluding 26 subcarriers, a second subcarrier allocation 522 may includea number of RUs each including 52 subcarriers, a third subcarrierallocation 523 may include a number of RUs each including 106subcarriers, a fourth subcarrier allocation 524 may include a number ofRUs each including 242 subcarriers, a fifth subcarrier allocation 525may include a number of RUs each including 484 subcarriers, and a sixthsubcarrier allocation 526 may include one RU including 996 subcarriers(with the left half of the channel for SU operations). For each of theexample subcarrier allocations 521-526 depicted in FIG. 5C, adjacent RUsmay be separated by a null subcarrier, for example, to reduce leakagebetween adjacent RUs.

An AP may allocate specific or dedicated RUs to a number of associatedSTAs using a trigger frame. In some implementations, the trigger framemay identify a number of STAs associated with the AP, and may solicituplink (UL) multi-user (MU) data transmissions from the identified STAsusing their allocated RUs. The trigger frame may use associationidentification (AID) values, assigned by the AP to its associated STAs,to identify which STAs are to transmit UL data to the AP in response tothe trigger frame. In some aspects, the trigger frame may indicate theRU size and location, the modulation and coding scheme (MCS), and thepower level for UL transmissions to be used by each of the STAsidentified in the trigger frame. As used herein, the RU size mayindicate the bandwidth of the RU, and the RU location may indicate whichfrequency subcarriers are allocated to the RU. A trigger frame thatallocates dedicated RUs to a number of associated STAs identified in thetrigger frame may be referred to herein as a “directed” trigger frame.

FIG. 6A shows a sequence diagram 600A depicting an example allocation ofdedicated resource units (RUs) to a number of wireless stations. The APof FIG. 6A may be any suitable AP including, for example, the AP 110 ofFIG. 1A, the AP 140 of FIG. 1B, or the AP 400 of FIG. 4. Each of thewireless stations STA1-STAn may be any suitable wireless stationincluding, for example, the stations STA1-STA4 of FIG. 1A, the stationsSTA1-STA99 of FIG. 1B, or the STA 300 of FIG. 3.

In some implementations, the AP may contend for medium access during abackoff period or a point coordination function (PCF) interframe space(PIFS) duration (such as between times t₁ and t₂). In otherimplementations, the AP may contend for medium access using anothersuitable channel access mechanism. In some other implementations, the APmay utilize a multiple channel access mechanism, for example, and maynot contend for medium access.

The AP gains access to the wireless medium at time t₂, and may transmita directed trigger frame 602 to the stations STA1-STAn on a downlink(DL) channel Time t₂ may indicate a beginning of a transmit opportunity(TXOP) 608. The directed trigger frame 602 may allocate a dedicated RUto each of a number of stations STA1-STAn identified by the directedtrigger frame 602 for uplink (UL) transmissions. In some aspects, thededicated RUs allocated by the directed trigger frame 602 may be unique,for example, so that the identified stations may transmit UL data to theAP at the same time (or at substantially the same time). The directedtrigger frame 602 also may solicit UL MU data transmissions fromstations identified by the directed trigger frame 602.

The stations STA1-STAn may receive the directed trigger frame 602 at (oraround) time t₃. Each of the stations STA1-STAn may decode a portion ofthe directed trigger frame 602 to determine whether the station isidentified by the directed trigger frame 602. In some aspects, thedirected trigger frame 602 may use AID values assigned to the stationsSTA1-STAn to identify which of the stations STA1-STAn have beenallocated dedicated RUs and to indicate which of the stations STA1-STAnare to transmit UL data based on reception of the directed trigger frame602. Each of the stations STA1-STAn that is not identified by thedirected trigger frame 602 may not transmit UL data during the TXOP 608,for example, because they may not have been allocated dedicated RUs forUL transmissions during the TXOP 608.

Each of the stations STA1-STAn that is identified by the directedtrigger frame 602 may decode additional portions of the directed triggerframe 602 to determine the size and location of the dedicated RUallocated thereto. In some aspects, the directed trigger frame 602 mayschedule UL data transmissions from the identified stations STA1-STAn tocommence at an unspecified interframe spacing (xIFS) duration afterreception of the directed trigger frame 602, for example, as depicted inFIG. 6A.

At time t₄, the stations STA1-STAn identified by the directed triggerframe 602 may begin transmitting UL MU data 604 on their respectivededicated RUs. In some aspects, each of the stations STA1-STAnidentified by the directed trigger frame 602 may determine whether thefrequency band associated with its allocated RU has been idle for aduration (such as a PIFS duration) prior to transmitting UL MU data tothe AP. For the example of FIG. 6A, all of the stations STA1-STAn areallocated a dedicated RU by the directed trigger frame 602, and all ofthe stations STA1-STAn transmit UL MU data to the AP using theirrespective dedicated RUs. In other implementations, a subset (such asless than all) of the stations STA1-STAn may be allocated dedicated RUsby the directed trigger frame 602.

The AP may receive the UL MU data 604 from the identified stationsSTA1-STAn at time t₅, and may acknowledge reception of the UL MU data604 from the stations STA1-STAn by transmitting acknowledgement (ACK)frames at time t₆. In some aspects, the AP may acknowledge reception ofthe UL MU data by transmitting an MU ACK frame to the stationsSTA1-STAn. In other aspects, the AP may acknowledge reception of the ULMU data by transmitting a multi-station block acknowledgement (M-BA)frame 606 to the stations STA1-STAn, for example, as depicted in FIG.6A.

In some implementations, the AP may transmit the M-BA frame 606 a shortinterframe spacing (SIFS) duration after receiving the UL MU datatransmitted from the stations STA1-STAn (as shown in FIG. 6A). In otherimplementations, the AP may transmit the M-BA frame 606 after anothersuitable duration.

In addition, or in the alternative, the AP may transmit a trigger framethat allocates random RUs to the stations STA1-STAn for UL datatransmissions. In some implementations, the random RUs may becontention-based resources that are shared by all STAs that receive thetrigger frame. The random RUs may be used by any STA that receives thetrigger frame, including STAs that are not associated with the AP.Allocation of the random RUs may allow STAs that were not identified inthe directed trigger frame 602 to transmit UL data to the AP (such as byusing the random RUs rather than the dedicated RUs allocated by thedirected trigger frame 602). The exclusion of a given STA from UL datatransmissions on dedicated RUs allocated by the directed trigger frame602 may be based on a variety of factors including, for example, afailure of the AP to receive a buffer status report (BSR) from the givenSTA, a limited number of dedicated RUs that may be allocated for UL MUdata transmissions, or the absence of an AID assigned to the given STA(such as because the given STA is not associated with the AP). A triggerframe that allocates random RUs (such as for OFDMA-based random channelaccess) to all receiving STAs may be referred to herein as a “wildcard”trigger frame.

FIG. 6B shows a sequence diagram 600B depicting an example allocation ofrandom RUs. The AP of FIG. 6B may be any suitable AP including, forexample, the AP 110 of FIG. 1A, the AP 140 of FIG. 1B, or the AP 400 ofFIG. 4. Each of the wireless stations STA1-STAn may be any suitablewireless station including, for example, the stations STA1-STA4 of FIG.1A, the stations STA1-STA99 of FIG. 1B, or the STA 300 of FIG. 3.

In some implementations, the AP may contend for medium access during abackoff period or a PIFS duration. In other implementations, the AP maycontend for medium access using another suitable channel accessmechanism. In some other implementations, the AP may utilize a multiplechannel access mechanism.

The AP gains access to the wireless medium at time t₂, and may transmita wildcard trigger frame 612 to the stations STA1-STAn on the DL channelTime t₂ may indicate a beginning of a transmit opportunity (TXOP) 618.The wildcard trigger frame 612 may allocate one or more random RUs uponwhich the stations STA1-STAn may transmit UL MU data to the AP. Thetrigger frame 612 may allocate random RUs using pre-defined AID values,for example, where an AID value=0 indicates the allocation of random RUsto associated STAs and an AID value=2045 indicates the allocation ofrandom RUs to un-associated STAs.

The stations STA1-STAn may receive the wildcard trigger frame 612 at (oraround) time t₃, and may contend with each other for access to theallocated random RUs. In some aspects, the wildcard trigger frame 612may be a broadcast frame that allows any receiving wireless device tocontend for access to the random RUs allocated by the wildcard triggerframe 612. In other aspects, the wildcard trigger frame 612 may be amulticast frame that allows a selected subset of the stations STA1-STAnto contend for access to the random RUs allocated by the wildcardtrigger frame 612.

In some implementations, the stations STA1-STAn may use the DCF or PCFback-off procedure to contend for access to the random RUs. In otherimplementations, the stations STA1-STAn may use an opportunisticback-off (OBO) procedure to contend for access to the random RUs, forexample, as depicted in the FIG. 6B. The OBO procedure is a distributedrandom channel access mechanism for which each STA selects a randomback-off number that may be used to select one of the random RUsallocated by the wildcard trigger frame 612. For example, if the APallocates four random RUs to be shared as contention-based resources,and a given STA selects an OBO value of 3, then the given STA maytransmit UL MU data using the third random RU. Conversely, if the givenSTA selects an OBO value of 5, then the given STA may not use the randomRUs to transmit UL data during the TXOP 618 (such as because the fourrandom RUs may be used by STAs that selected OBO values of 1 through 4).After expiration of the TXOP 618, the given STA may update its OBO valuefrom 5 to 1, and then transmit UL MU data using the first random RUduring a next TXOP.

For the example of FIG. 6B, stations STA1 and STA2 gain access to therandom RUs allocated by the wildcard trigger frame 612 at time t₄, andbegin transmitting UL MU data 614 to the AP during the TXOP 618. Theother stations (such as stations STA3-STAn) may not use the random RUsallocated by the wildcard trigger frame 612 to transmit UL data duringthe TXOP 618, for example, because their initial OBO values may begreater than the number of random RUs allocated by the wildcard triggerframe 612.

The AP may receive the UL MU data 614 from stations STA1 and STA2 attime t₅, and may acknowledge reception of the UL MU data 614 bytransmitting acknowledgement (ACK) frames at time t₆. In some aspects,the AP may acknowledge reception of the UL MU data 614 by transmittingan MU ACK frame to stations STA1 and STA2. In other aspects, the AP mayacknowledge reception of the UL MU data 614 by transmitting amulti-station block acknowledgement (M-BA) frame 616 to stations STA1and STA2, for example, as depicted in FIG. 6B.

Referring again to FIG. 1B, the AP 140 may create and independentlyoperate a plurality of basic service sets BSS0-BSSk (such as by usingthe virtual access points VAP1-VAPk), and each of the basic service setsBSS0-BSSk may include a different number of wireless devices orstations. In some implementations, the AP 140 may assign each of theexample stations STA1-STA99 of FIG. 1B to a particular one of the basicservice sets BSS0-BSSk based on a number of parameters of one or more ofthe basic service sets BSS0-BSSk. In some aspects, the number ofparameters of a given one of the basic service sets BSS0-BSSk mayinclude one or more of: security parameters of the given BSS, accessprivileges of the wireless devices associated with or belonging to thegiven BSS, the types of wireless devices (such as IoT devices, Wi-Fidevices, and so on) associated with or belonging to the given BSS,quality of service (QoS) parameters of the given BSS, delay requirements(such as relatively short delays for voice traffic and relatively longdelays for background or best effort traffic) of the wireless devicesassociated with or belonging to the given BSS, bandwidth capabilities ofthe wireless devices associated with or belonging to the given BSS (suchas narrowband capabilities and wideband capabilities), and any othersuitable metric or characteristic that may be used to prioritize theallocation of random RUs to the plurality of basic service setsBSS0-BSSk.

FIG. 7 shows a sequence diagram 700 depicting an example allocation ofrandom RUs to a specific basic service set (BSS). The AP of FIG. 7 maybe any suitable AP including, for example, the AP 110 of FIG. 1A, the AP140 of FIG. 1B, or the AP 400 of FIG. 4. The example operation of FIG. 7is described below with respect to the multiple BSSID set 130 of FIG.1B, and the AP of FIG. 7 is associated with the Tx BSSID. Thus, for theexample operation of FIG. 7, the basic service set BSS0 of FIG. 1B isdesignated as the Tx BSSID, and each of the other basic service setsBSS1-BSSk of FIG. 1B is designated as a non-Tx BSSID. Although not shownfor simplicity, each of the non-Tx BSSIDs may be operated by anassociated AP (or an associated virtual AP such as one of the virtualaccess points VAP1-VAP7 of FIG. 1B).

In some implementations, the AP may contend for medium access during abackoff period or a point coordination function (PCF) interframe space(PIFS) duration (such as between times t₁ and t₂). In otherimplementations, the AP may contend for medium access using anothersuitable channel access mechanism. In some other implementations, the APmay utilize a multiple channel access mechanism, for example, and maynot contend for medium access.

The AP gains access to the wireless medium at time t₂, and may transmita trigger frame 712 on a DL channel to the stations STA1-STA99 belongingto the multiple BSSID set 130. Time t₂ may indicate a beginning of atransmit opportunity (TXOP) 701. The trigger frame 712 may allocate oneor more random RUs to each of a selected number of the plurality ofbasic service sets BSS0-BSSk, for example, so that the stations (orother wireless devices) associated with the selected BSSs may transmitUL data to the AP (or to other devices) using the random RUs allocatedby the trigger frame 712. In some implementations, the trigger frame 712may contain one or more values identifying the selected BSSs, and mayindicate the size and location of the random RUs allocated to each ofthe selected BSSs. The selected number of BSSs may be a subset of theBSSs operated or controlled by the AP, for example, so that the randomRUs allocated by the AP are not available to all BSSs operated orcontrolled by the AP.

In some implementations, the trigger frame 712 may allocate one or morerandom RUs to a selected BSS, rather than to specific stations, bysetting one of its AID values to the BSSID index assigned to theselected BSS. In some aspects, random RUs allocated to the selected BSSby the trigger frame 712 may be shared by any number of the stationsassociated with the selected BSS. Thus, rather than identifying aparticular station to which one or more random RUs are allocated, eachAID value provided in the trigger frame 712 may identify a particularBSS to which one or more random RUs are allocated.

In some aspects, the trigger frame 712 may be a broadcast frame thatallows any stations (or other wireless devices) associated with theselected BSSs to contend for access to the random RUs allocated by thetrigger frame 712. In other aspects, the trigger frame 712 may be amulticast frame that allows a group of stations associated with theselected BSSs to contend for access to the random RUs allocated by thetrigger frame 712.

Stations within range of the AP 110 may receive the trigger frame 712 at(or around) time t_(3A). Each of the stations that receives the triggerframe 712 may decode the AID value(s) included in the trigger frame 712to determine whether the BSS to which the station belongs has beenallocated random RUs. In some implementations, if a given stationdetermines that an AID value included in the trigger frame 712 matchesthe BSSID index of its associated BSS, then the given station maycontend for access to the random RUs allocated by the trigger frame 712.Conversely, if a given station determines that the trigger frame 712does not include an AID value that matches the BSSID index of itsassociated BSS, then the given station may not contend for access to therandom RUs allocated by the trigger frame 712.

For the example of FIG. 7, the AP selects the basic service set BSS1 forallocation of the random RUs, and an AID value contained in the triggerframe 712 is set to the BSSID index of the basic service set BSS1 (suchas AID=BSSID index=1). Because the stations STA10-STA50 are associatedwith the basic service set BSS1 assigned to a BSSID index=1, thestations STA10-STA50 may contend with each other for access to therandom RUs allocated by the trigger frame 712 at time t_(3B) (which maybe an xIFS duration after time t_(3A)). Stations that are not associatedwith the selected BSS (such as stations STA51-STA99 of FIG. 1B) may notcontend for access to the random RUs allocated by the trigger frame 712.In some aspects, stations that are not associated with the selected BSSmay return to a power save state.

The first station STA10 associated with the selected basic service setBSS1 is depicted as gaining access to the wireless medium (after abackoff period between times t_(3B) and t₄), and begins transmitting ULdata on the random RU allocated by the trigger frame 712 at time t₄. Insome aspects, the first station STA10 may use the random RU to transmitUL data within its associated basic service set BSS1. In other aspects,the first station STA10 may use the random RU to transmit UL data towireless devices associated with other basic service sets.

The AP may receive the UL MU data 714 from the first station STA10 attime t₅, and may acknowledge reception of the UL MU data 714 bytransmitting an M-BA frame 716 to the first station STA10 at time t₆. Inother aspects, the AP may acknowledge reception of the UL MU data 714 bytransmitting an MU ACK frame to the first station STA10.

The ability to allocate random RUs for use by stations associated with aspecific basic service set of a multiple BSSID set using a trigger framemay increase medium utilization and efficiency (as compared toallocating random RUs to all of the stations in the multiple BSSID set).For one example, if a first BSS includes 100 wireless devices and asecond BSS includes 3 wireless devices, then allocating random RUs toall wireless devices associated with the AP may result in the wirelessdevices belonging to the second BSS receiving a disproportionate shareof the random RUs allocated by the AP. Thus, by allocating random RUs towireless devices belonging to the first BSS (rather than to wirelessdevices belonging to all BSSs operated or controlled by the AP), the APmay prioritize the allocation of random RUs based on the number ofwireless devices that belong to the first BSS. In other words, becausemore wireless devices belong to the first BSS than to the second BSS,the AP may allocate more random RUs to the first BSS than to the secondBSS (or may allocate random RUs to the first BSS more frequently than tothe second BSS).

For another example, if a first BSS includes 4 smartphones thatfrequently implement VoIP calls and a second BSS includes 10 IoT devices(such as smart sensors), then allocating random RUs to all wirelessdevices associated with the AP using conventional RU allocationtechniques may result in allocations of random RUs to sensor devices(which typically do not have delay-critical traffic) that wouldotherwise be available to facilitate VoIP calls and other real-timetraffic corresponding to the first BSS. Thus, by allocating random RUsto the 4 smartphones belonging to the first BSS (and not to the 10 IoTdevices belonging to the second BSS), the AP may prioritize theallocation of random RUs based on traffic classes and delay or latencyrequirements.

In some other implementations, a trigger frame may be defined that canallocate dedicated RUs to one or more identified STAs, can allocaterandom RUs to one or more specific basic service sets belonging to amultiple BSSID set (and thereby allow a number of STAs to share theallocated random RUs irrespective of whether the STAs are associatedwith the Tx BSSID or with one of the non-Tx BSSIDs and/or can allocaterandom RUs to unassociated STAs. In other words, an AP corresponding tothe Tx BSSID of a multiple BSSID set can use trigger frames disclosedherein to allocate dedicated RUs to STAs belonging to the Tx BSSID, toallocate dedicated RUs to STAs belonging to any of the non-Tx BSSIDs, toallocate random RUs to be shared by the STAs belonging to the Tx BSSID,to allocate random RUs to be shared by the STAs belonging to any of thenon-Tx BSSIDs, to allocate random RUs to be shared by all the STAsbelonging to the multiple BSSID set, to allocate random RUs to be sharedby all unassociated STAs, or any combination thereof.

In some aspects, the STAs belonging to the multiple BSSID set canindicate their ability to receive multi-BSS control frames by settingthe RX multi-BSS Control Frame bit in a HE Capabilities element, forexample, during discovery operations (such as in a probe request frame)or during association operations (such as in an association requestframe). In other aspects, the STAs can indicate their ability to receivemulti-BSS control frames in any other suitable element.

The ability of an AP associated with the Tx BSSID to solicit UL datatransmissions from individual STAs belonging to the multiple BSSID set,irrespective of which BSSID the individual STAs belong to, may allow theAP to coordinate the allocation of not only dedicated RUs but alsorandom RUs on both a per-BSS basis and on a per-STA basis. This mayallow the AP to increase the fairness with which the STAs belonging tothe multiple BSSID set are given the opportunity to contend for accessto random RUs. In some implementations, the AP can use trigger framesdisclosed herein to adjust the allocation of random RUs between the STAsbelonging to the multiple BSSID set based on a number of factorsincluding, for example, the number of STAs associated with each of theBSSs, the traffic types of each of the BSSs, the priority levels oftraffic flows in each of the BSSs, congestion in each of the BSSs, andso on.

FIG. 8 shows a sequence diagram depicting an example operation 800 forallocating dedicated RUs and random RUs for use by a number of STAsbelonging to a multiple BSSID set. The example operation 800 isdescribed below with respect to the multiple BSSID set 130 of FIG. 1B,and may be performed by an AP that operates the BSS corresponding to theTx BSSID. Although not shown in FIG. 8 for simplicity, the multipleBSSID set includes a Tx BSSID and seven non-Tx BSSIDs. Referring also toFIG. 1B, the AP that transmits trigger frames in the example operation800 is associated with the Tx BSSID, and may be referred to as the TxAP. Each of the non-Tx BSSIDs may be associated with another AP (such asa respective one of the access points AP1-AP7 or a respective one of thevirtual access points VAP1-VAP7). The APs (or virtual APs) associatedwith the non-Tx BSSID may be referred to as non-Tx APs.

For the example of FIG. 8, station STA1 is associated with the Tx BSSID(which has a BSSID index=0) and is assigned AID=14, station STA2 isassociated with a non-Tx BSSID having a BSSID index=1 and is assignedAID=17, station STA3 is associated with a non-Tx BSSID having a BSSIDindex=2 and is assigned AID=8, station STA4 is associated with a non-TxBSSID having a BSSID index=3 and is assigned AID=16, station STA5 isassociated with the Tx BSSID=0 and is assigned AID=9, and station STA6is associated with a non-Tx BSSID having a BSSID index=2 and is assignedAID=15.

Prior to the operation 800, the Tx AP may announce that it belongs to amultiple BSSID set and advertise its multiple BSSID capabilities using amultiple BSSID element contained in a management frame (such as a beaconframe or a probe response frame). Nearby STAs may indicate their supportfor the Multiple BSSID capability using by setting a bit in the ExtendedCapabilities element of a suitable response frame. In addition, or inthe alternative, nearby STAs may include the Extended Capabilitieselement in a probe request frame transmitted to the AP. Although thenon-Tx APs corresponding to the non-Tx BSSIDs may not transmitmanagement frames containing a multiple BSSID element, the multipleBSSID capabilities of the non-Tx APs can be announced or advertised inone or more Multiple BSSID elements transmitted by the Tx AP. In someaspects, one or more management frames (such as beacon frames or proberesponse frames) transmitted by the Tx AP may contain a number of non-TxBSSID profiles 205 that indicate the multiple BSSID capabilities of thenon-Tx BSSIDs.

In accordance with aspects of the present disclosure, each of the APsbelonging to the multiple BSSID set may announce or advertise its ownrandom access parameter set (RAPS) element. The RAPS elements may signalone or more metrics of an OFDMA-based random access mechanism. Each RAPSelement may include an OFDMA Contention Window (OCW) range field thatstores a minimum OCW value and a maximum OCW value for a correspondingAP. During random channel access operations, each of the receivingstations may select an OBO count value that is between the minimum OCWvalue and the maximum OCW value indicated in the corresponding RAPSelement. For example, when a trigger frame allocates random RUs for useby STAs belonging to the multiple BSSID set, a STA that receives thetrigger frame may select a OBO count value that is between the minimumOCW value and the maximum OCW value signaled for its correspondingBSSID. In some aspects, each of the non-Tx BSSIDs may select its ownRAPS value based on, for example, the number of associated STAs. Inother implementations, a particular non-Tx BSSID may be configured (suchas by a user or network administrator) to not allocate random RUs to itsassociated STAs. In some aspects, the particular non-Tx BSSID mayindicate that it does not support random access feature and does notallocate random RUs by advertising a RAPS element that includes aspecial value or a dedicated field explicitly indicating that theparticular non-Tx BSSID does not allocate random RUs. In other aspects,the particular non-Tx BSSID may indicate that it does not allocaterandom RUs by advertising a null RAPS element. For example, the nullRAPS element may be a RAPS element that includes only an element IDfield and a length field (which may be set to 1). Null RAPS elements aredescribed in more detail below with respect to FIG. 10C.

In some implementations, the RAPS elements of the non-Tx BSSIDs may beannounced in management frames transmitted by the Tx AP. In someaspects, the RAPS elements may be provided in the non-Tx BSSID profiles205 of multiple BSSID elements 200 contained in the management frame. Inthis manner, all the STAs belonging to the multiple BSSID set maydetermine their minimum and maximum OCW values from the managementframes. If the RAPS element of a particular non-Tx BSSID is not includedin management frames transmitted by the Tx BSSID, or if the particularnon-Tx BSSID does not advertise or otherwise provide its RAPS element toits associated STAs, then the STAs associated with the particular non-TxBSSID may use the RAPS element of the Tx BSSID to determine the minimumand maximum OCW values for random access channel operations. In thismanner, STAs that do not receive a RAPS element from their associatedAPs may “inherit” the RAPS elements of the Tx BSSID. In other aspects,if the non-Tx BSSID transmits a RAPS element that is different from theRAPS of the (if your AP transmits it, follow it; if it doesn't, theninherit the RAPS from the Tx BSSID.

At time t₁, the Tx AP transmits a management frame 810. The managementframe 810 is shown to include a transmitter address (TA) field, amultiple BSSID element, a number of non-Tx BSSID profiles, and a RUallocation bitmap. The TA field may store the transmitter address of theTx AP, for example, to indicate that the Tx AP corresponds to the TxBSSID. Thus, for the example of FIG. 8, the TA field of the managementframe 810 may store a BSSID index=0. The non-Tx BSSID profiles, whichmay be one implementation of the non-Tx BSSID profile 205 of FIG. 2A,may contain a list of elements for one or more of the other accesspoints AP1-AP7 corresponding to the non-Tx BSSIDs. In some aspects, thenon-Tx BSSID profile contained in the management frame 810 may contain anon-Tx BSSID capabilities element 210, an SSID and BSSID-index element220, and an FMS descriptor element 230. The RU allocation bitmap maystore a bitmap indicating the allocation of dedicated RUs to one or moreidentified STAs and the allocation of random RUs to individual BSSIDs orto groups of STAs (such as the STAs associated with a selected number ofthe BSSIDs) belonging to the multiple BSSID set.

Each STA that receives the management frame 810 may examine one of thebits B0-B7 in the BSSID portion 242A of the partial virtual bitmap 242to determine a presence of group address traffic for a corresponding oneof the BSSIDs belonging to the multiple BSSID set, and may examine oneof the bits in the STA portion 242B of the partial virtual bitmap 242 todetermine a presence of DL data for the STA. More specifically, aparticular STA that receives the management frame 810 may determinewhether any of the BSSIDs has DL data for the STA by examining two bitsin the partial virtual bitmap of the TIM element: the bit in the BSSIDportion of the partial virtual bitmap corresponding to the BSSID withwhich the particular STA is associated, and the bit in the STA portionof the partial virtual bitmap corresponding to the AID value assigned tothe particular STA.

After gaining access to the wireless medium, the Tx AP transmits a firsttrigger frame 812A at time t₂ (which may indicate a beginning of a firstTXOP 801). When the first trigger frame 812A is transmitted from the TxBSSID, the transmitter address (TA) of the first trigger frame 812A isset to the MAC address of the Tx BSSID. The first trigger frame 812A mayallocate dedicated RUs to one or more identified STAs and/or mayallocate random RUs to individual BSSIDs or to groups of STAs (such asthe STAs associated with each of a selected number of the BSSIDs). Inaccordance with some aspects of the present disclosure, the Tx AP mayallocate random RUs to individual BSSIDs and/or to groups of STAs usingAID values contained in one or more of the Per User Info fields of thefirst trigger frame 812A. In some implementations, the first triggerframe 812A may leverage the group-AID mappings in the partial virtualbitmap contained in the management frame 810 to identify specific BSSIDsand/or specific groups of stations using AID values.

In some aspects, the first trigger frame 812A may allocate random RUs tobe shared by the STAs associated with the Tx BSSID by setting an AIDvalue=0, for example, based on the Tx BSSID having a BSSID index=0. EachSTA that receives the first trigger frame 812A may determine whether anyrandom RUs are allocated to all of the STAs belonging to the multipleBSSID set by determining whether the first trigger frame 812A sets anAID value=0.

In some aspects, the first trigger frame 812A may allocate random RUs tobe shared by the STAs associated with a selected non-Tx BSSID by settingan AID to the BSSID index of the selected non-Tx BSSID (based onmappings between the non-Tx BSSID's index and a corresponding AID valuein the partial virtual bitmap). For example, the first trigger frame812A may allocate random RUs to be shared by all STAs associated withthe first non-Tx BSSID by setting an AID value=1, may allocate randomRUs to be shared by all STAs associated with the second non-Tx BSSID bysetting an AID value=2, may allocate random RUs to be shared by all STAsassociated with the third non-Tx BSSID by setting an AID value=3, and soon. Each STA that receives the first trigger frame 812A may determinewhether any random RUs are allocated to the STA's basic service set bydetermining whether the first trigger frame 812A contains an AID set tothe BSSID of its associated AP.

In some aspects, the first trigger frame 812A may also allocatededicated RUs to an individual STA associated with any of the basicservice sets belonging to the multiple BSSID set by setting an AID valueto the AID assigned to the individual STA. For example, the firsttrigger frame 812A may allocate dedicated RUs to STA5 of FIG. 8 bysetting an AID value=9 (which is the AID value assigned to STA5). EachSTA that receives the first trigger frame 812A may determine whether anyrandom RUs are allocated for use by the STA by determining whether thefirst trigger frame 812A sets an AID value to the BSSID of itsassociated AP. In some aspects, the first trigger frame 812A mayallocate random RUs to unassociated STAs by setting an AID value=2045.

In other implementations, the first trigger frame 812A may betransmitted by a non-Tx BSSID (such as by one of the other access pointsAP1-AP7). When transmitted by a non-Tx BSSID, the first trigger frame812A may include a TA set to the BSSID index of the non-Tx BSSID, andmay allocate random RUs to be shared by STAs associated with that non-TxBSSID, for example, by setting an AID value=0. In addition, or in thealternative, the first trigger frame 812A may allocate random RUs foruse by all unassociated stations by setting an AID value to 2045.

Because each STA in the multiple BSSID set stores the BSSID-index of itsassociated AP and also stores its assigned AID value, each STA in themultiple BSSID set may readily determine whether the first trigger frame812A allocates random RUs for use by the STA based on two AIDs containedin the first trigger frame 812A: the AID corresponding to the BSSIDindex of the STA's associated AP, and the AID corresponding to the AIDvalue assigned to the STA.

As depicted in the example operation 800 of FIG. 8, the first triggerframe 812A allocates a first resource unit RU1 as a random RU for use byall un-associated STAs by setting an AID value=2045, allocates a secondresource unit RU2 as a random RU for use by the STAs associated with thebasic service set having a BSSID index=3 by setting an AID value=3,allocates a third resource unit RU3 as a random RU for use by the STAsassociated with the basic service set having a BSSID index=2 by settingan AID value=2, allocates a fourth resource unit RU4 as a random RU foruse by the STAs associated with the basic service set having a BSSIDindex=1 by setting an AID value=1, allocates a fifth resource unit RU5as a random RU for use by the STAs associated with the Tx BSSID bysetting an AID value=0, and allocates a sixth resource unit RU6 as adedicated RU to STA5 by setting an AID value=9.

The STAs may receive the first trigger frame 812A at (or around) timet₃. Each STA that receives the first trigger frame 812A may decode theRU allocation bitmap included in the first trigger frame 812A todetermine whether any RUs are allocated or otherwise available to theSTA. More specifically, each receiving STA may decode the AID valuesprovided in the RU allocation bitmap to determine whether the triggerframe 812A allocated a dedicated RU to the STA or allocated one or morerandom RUs for which the STA may contend (such as by using the OBOprocedure).

At time t₄, the STAs that were allocated either a dedicated RU or thatgained access to one of the random RUs begin transmitting UL data 814Ato the Tx AP. For the example of FIG. 8, one of the un-associated STAstransmits UL data on the first resource unit RU1, one of the STAsassociated with BSSID=3 transmits UL data on the second resource unitRU2, one of the STAs associated with BSSID=2 transmits UL data on thethird resource unit RU3, one of the STAs associated with BSSID=1transmits UL data on the fourth resource unit RU4, one of the STAsassociated with the Tx BSSID transmits UL data on the fifth resourceunit RU5, and STA5 transmits UL data on the sixth resource unit RU6.

The Tx AP receives the UL data transmissions 814A at time t₅, and mayacknowledge reception by transmitting an M-BA frame (not shown forsimplicity). Thereafter, the Tx AP may transmit a second trigger frame812B at time t₆ (which may indicate a beginning of a second TXOP 802).In the example operation 800 of FIG. 8, the second trigger frame 812Ballocates the first resource unit RU1 as a random RU to the STAsassociated with BSSID=2 by setting AID=0, allocates the second resourceunit RU2 as a random RU to the STAs associated with BSSID=2 by setting acorresponding AID=0, allocates the third resource unit RU3 as adedicated RU to STA6 by setting a corresponding AID=5, and allocates thefourth resource unit RU4 as a dedicated RU to STA5 by settingcorresponding AID=8.

Each of the STAs may receive the second trigger frame 812B at (oraround) time t₇, and may decode the RU allocation bitmap included in thesecond trigger frame 812B to determine whether any RUs are allocated orotherwise available to the STA. STAs that were either allocateddedicated resources or that gained access to random RUs begintransmitting UL data 814B at time t₈. In the example operation 800 ofFIG. 8, one of the STAs associated with BSSID=2 transmits UL data on thefirst resource unit RU1 based on the value AID=0 in the RU allocationbitmap, one of the STAs associated with BSSID=2 transmits UL data on thesecond resource unit RU2 based on the value AID=0 in the RU allocationbitmap, STA6 transmits UL data on the third resource unit RU3 based onthe value AID=5 in the RU allocation bitmap, and STA4 transmits UL dataon the fourth resource unit RU4 based on the value AID=6 in the RUallocation bitmap. The Tx AP may receive the UL data transmissions 814Bat time t₉, and may acknowledge reception by transmitting an M-BA frame(not shown for simplicity).

By allowing the Tx AP to allocate random RUs to STAs that are associatedwith the Tx BSSID and to STAs that are associated with one or morenon-Tx BSSIDs, aspects of the present disclosure may isolate collisionson the wireless medium within each of the different BSSs that form themultiple BSSID set. In addition, because STAs already keep track oftheir associated BSSID's index value, STAs belonging to the multipleBSSID set can determine whether trigger frames disclosed herein allocaterandom RUs to their own BSSID or to one of the non-Tx BSSIDs withoutstoring additional information.

In some other implementations, each of the APs (or virtual accesspoints) in the multiple BSSID set may announce or advertise its own RAPSelement, for example, using the non-Tx BSSID Profile contained in theMultiple BSSID element. For such implementations, the Tx BSSID mayannounce or advertise its own RAPS element in one or more beacon frames,and each of the non-Tx BSSIDs may select their RAPS values based on thenumber of STAs associated therewith. If a given non-Tx BSSID does notadvertise its own RAPS value, then the STAs associated with given non-TxBSSID may obtain the RAPS value from the Tx BSSID's RAPS element.

In some aspects, a trigger frame having a transmitter address set to aspecific non-Tx BSSID can allocate random RUs only to STAs that areassociated with the specific non-Tx BSSID. In some aspects, a random RUmay have an AID12=0. In addition, or in the alternative, a random RUallocated in a trigger frame having a transmitter address set to the TxBSSID can be used only by STAs associated with the Tx BSSID. For theseimplementations, collisions may remain isolated for each of the APs (orvirtual APs).

In some other implementations, each AP (or virtual AP) advertises itsown RAPS element, and the AP associated with the Tx BSSID transmits thebeacon frames. The non-Tx BSSIDs advertise their RAPS values using thenon-Tx BSSID Profile contained in the Multiple BSSID element. The non-TxBSSIDs may select their RAPS values based on the number of STAsassociated therewith. If a given non-Tx BSSID does not advertise its ownRAPS value, then the STAs associated with the given non-Tx BSSID may useRAPS element provided by the Tx BSSID. A random RU in a trigger framewith a transmitter address set to the non-Tx BSSID may be used only bySTAs associated with that non-Tx BSSID. In some aspects, a random RU mayhave an AID12=0, and a random RU allocated in a trigger frame having atransmitter address set to the Tx BSSID can be used by STAs associatedwith the multiple BSSID set.

In some aspects, STAs belonging to non-Tx BSSID may use the RAPS elementadvertised by the Tx BSSID. In other aspects, STAs belonging to one ofthe non-Tx BSSIDs may apply a scaling factor to account for differencesbetween the RAPS element of the Tx BSSID and the RAPs value of their ownBSSID. These implementations may increase collisions between STAsbecause a large number of STAs may try to access the random RUs, and mayincrease complexity because the STAs needs to track two RAPS values(rather than one RAPS value).

In some other implementations, only the Tx BSSID advertises its RAPSelement. In some aspects, the non-Tx BSSID may use the RAPS elementprovided by the Tx BSSID. When a trigger frame with a transmitteraddress set to the Tx BSSID allocates random RUs, then either (1) onlySTAs associated with the Tx BSSID can use the random RUs, or (2) any STAbelonging to the multiple BSSID set can use the random RUs. Only STAsassociated with a non-Tx BSSID can use random RUs when the trigger framehas a transmitter address set to a non-Tx BSSID. In other aspects, onlytrigger frames sent by the Tx BSSID can allocate random RUs. Any STA ofthe multiple BSSID set can use RUs for random access.

In some implementations, unassociated STAs that have not received RAPSinformation from an AP may use a default RAPS parameter value (or OBOcounter value) when initially communicating with the AP using randomaccess channel mechanisms.

FIG. 9 shows an example trigger frame 900. The trigger frame 900 may beused as the directed trigger frame 602 of FIG. 6A, the wildcard triggerframe 612 of FIG. 6B, the trigger frame 712 of FIG. 7, or the triggerframes 812A-812B of FIG. 8. The trigger frame 900 is shown to include aframe control field 901, a duration field 902, a receiver address (RA)field 903, a transmitter address (TA) field 904, a Common Info field905, a number of Per User Info fields 906(1)-906(n), and a frame checksequence (FCS) field 907.

The frame control field 901 includes a Type field 901A and a Sub-typefield 901B. The Type field 901A may store a value to indicate that thetrigger frame 900 is a control frame, and the Sub-type field 901B maystore a value indicating a type of the trigger frame 900. The durationfield 902 may store information indicating a duration or length of thetrigger frame 900. The RA field 903 may store the address of a receivingdevice (such as one of the wireless stations STA1-STAn of FIGS. 6A, 6B,and 7). The TA field 904 may store the address of a transmitting device(such as the AP of FIGS. 6A, 6B, 7, and 8). The Common Info field 905may store information common to one or more receiving devices, asdescribed in more detail below with respect to FIG. 10A. Each of the PerUser Info fields 906(1)-906(n) may store information for a particularreceiving device including, for example, the AID of the receivingdevice. The FCS field 907 may store a frame check sequence (such as forerror detection).

In some aspects, the trigger frame 900 may allocate dedicated RUs toassociated STAs identified by AID values stored in corresponding ones ofthe Per User Info fields 906(1)-906(n). In other aspects, the triggerframe 900 may allocate random RUs to one or more groups of STAs usingpre-defined AID values stored in the Per User Info fields 906(1)-906(n).For example, as described above, setting AID=0 in a trigger frame mayallocate random RUs to STAs associated with the Tx AP, while setting anAID=2045 in a trigger frame may allocate random RUs to non-associatedSTAs.

FIG. 10A shows an example Common Info field 1000. The Common Info field1000 may be one implementation of the Common Info field 905 of thetrigger frame 900. The Common Info field 1000 is shown to include alength subfield 1001, a cascade indication subfield 1002, ahigh-efficiency signaling A (HE-SIG-A) info subfield 1003, a cyclicprefix (CP) and legacy training field (LTF) type subfield 1004, atrigger type subfield 1005, and a trigger-dependent common info subfield1006. The length subfield 1001 may indicate the length of a legacysignaling field of the UL data frames to be transmitted in response tothe trigger frame 900. The cascade indication subfield 1002 may indicatewhether a subsequent trigger frame follows the current trigger frame.The HE-SIG-A Info subfield 1003 may indicate the contents of a HE-SIG-Afield of the UL data frames to be transmitted in response to the triggerframe 900. The CP and LTF type subfield 1004 may indicate the cyclicprefix and HE-LTF type of the UL data frames to be transmitted inresponse to the trigger frame 900. The trigger type subfield 1005 mayindicate the type of trigger frame. The trigger-dependent common infosubfield 1006 may indicate trigger-dependent information.

FIG. 10B shows an example Per User Info field 1010. The Per User Infofield 1010 may be one implementation of the Per User Info fields906(1)-906(n) of the trigger frame 900. The Per User Info field 1010 isshown to include a User Identifier subfield 1011, an RU Allocationsubfield 1012, a Coding Type subfield 1013, an MCS subfield 1014, adual-carrier modulation (DCM) subfield 1015, a spatial stream (SS)Allocation subfield 1016, and a trigger-dependent Per User info subfield1017. The User Identifier subfield 1011 may indicate the associationidentification (AID) of the STA to which a dedicated RU is allocated fortransmitting UL MU data. The RU Allocation subfield 1012 may identifythe dedicated RU allocated to the corresponding STA (such as the STAidentified by the User Identifier subfield 1011). The Coding Typesubfield 1013 may indicate the type of coding to be used by thecorresponding STA when transmitting UL data using the allocated RU. TheMCS subfield 1014 may indicate the MCS to be used by the correspondingSTA when transmitting UL data using the allocated RU. The DCM subfield1015 may indicate the dual carrier modulation to be used by thecorresponding STA when transmitting UL data using the allocated RU. TheSS Allocation subfield 1016 may indicate the number of spatial streamsto be used by the corresponding STA when transmitting UL data using theallocated RU.

In some implementations, the value of the AID stored in the UserIdentifier subfield 1011 of the Per User Info field 1010 of the triggerframe 900 may indicate or identify the selected BSS to which random RUsidentified in the RU Allocation subfield 1012 are allocated. In someaspects, the AID stored in the User Identifier subfield 1011 may be oneof a number (N) of values, for example, to identify a corresponding oneof N different BSSs to which one or more random RUs are allocated by thetrigger frame 900. For one example in which the AP operates a number N=8of independent BSSs, AID values of 0-7 may be used by the trigger frame900 to identify a selected one of eight (8) BSSs to which the random RUsare allocated by the trigger frame 900. Thus, if the trigger frame 900sets AID=1, then all wireless devices associated with or belonging to aBSS having a BSSID index=1 (such as the first basic service set BSS1 ofFIG. 1B) may contend for access to the random RUs allocated by thetrigger frame 900; if the trigger frame 900 sets AID=2, then allwireless devices associated with or belonging to a BSS having a BSSIDindex=2 (such as the second basic service set BSS2 of FIG. 1B) maycontend for access to the random RUs allocated by the trigger frame 900;and so on.

Mappings between BSSID index values and AID values may be stored in theAP, for example, as described above with respect to FIG. 4. The AP mayshare the mappings between BSSID index values and AID values with itsassociated wireless devices. In some implementations, the AP maytransmit one or more multiple BSSID elements in management frame (suchas beacon frame or a probe response frame). The one or more multipleBSSID elements may be included in an information element (IE), in avendor-specific information element (VSIE), in a packet extension, or inany other suitable portion or field of a management frame.

FIG. 10C shows an example RAPS element 1020 (which may also be referredto an UL OFDMA-based Random Access (UORA) Parameter Set element). TheRAPS element 1020 is shown to include an element ID field 1021, a lengthfield 1022, an element ID extension field 1023, and an OCW range field1024. The element ID field 1021 may store a value (e.g., 255) indicatingthat the element is an extended type element and the element IDextension field 1023 may indicate element type (such as a RAPS element).The length field 1022 may store a value indicating a length of the RAPSelement 1020. The OCW range field 1024 may indicate the minimum andmaximum values of the OCW (OFDMA contention window).

As described above, a particular non-Tx BSSID may not allocate randomRUs to its associated STAs. In some implementations, the particularnon-Tx BSSID may indicate that it does not allocate random RUs byincluding, in the RAPS element 1020, a special value or dedicated field(not shown for simplicity) explicitly indicating that the particularnon-Tx BSSID does not allocate random RUs. In other implementations, theparticular non-Tx BSSID may indicate that it does not allocate randomRUs by advertising a null RAPS element. In some aspects, the particularnon-Tx BSSID may include a null RAPS element by omitting the Informationfield in the element (i.e., the OCW range field 1024 of the RAPS element1020), for example, such that the RAPS element 1020 includes only theelement ID field 1021, the element ID extension field 1023, and thelength field 1022 (which may be set to 1). Stations receiving a nullRAPS element may determine that the transmitting AP, or the APcorresponding to the null RAPSs element, does not allocate random RUs.

FIG. 11A shows an illustrative flow chart depicting an example operation1100 for allocating wireless resources to a multiple basic service setidentifier (BSSID) set. The multiple BSSID set may include a number ofBSSIDs each associated with a corresponding one of a number of accesspoints (APs). The example operation 1100 is performed by a first accesspoint (AP). The first AP may be the AP 110 of FIG. 1A, the AP 140 ofFIG. 1B, the AP 400 of FIG. 4, or any other suitable AP.

The first AP may allocate random access resources for use by stationsbelonging to the multiple BSSID set using a number of associationidentifier (AID) values based on a group AID mapping contained in apartial virtual bitmap of a traffic indication map (TIM) element (1101).The trigger frame may solicit uplink (UL) transmissions from stations onthe allocated random access resources. In some aspects, the number ofAID values contained in the trigger frame may identify, for theallocation of the random access resources, at least one of a group ofstations, a specific BSSID, a group of BSSIDs, and all of the stationsbelonging to the multiple BSSID set. For example, when the trigger frameis transmitted by Tx BSSID (such as the transmitter address (TA) is setto the MAC address of the Tx BSSID), a resource unit in the triggerframe corresponding to an AID value of zero (0) may indicate that randomaccess resources are available for STAs associated with the Tx BSSID, aresource unit in the trigger frame corresponding to an AID value of n(where 0<k<2^(n)) may indicate that random access resources areavailable STAs associated with the non-Tx BSSID assigned a BSSIDindex=k, a resource unit in the trigger frame corresponding to an AIDvalue set to a first special value (such as AID=2047) may indicate thatrandom access resource are available for all STAs belonging to themultiple BSSID set, and a resource unit in the trigger framecorresponding to an AID value set to a second special value (such asAID=2045) may indicate that random access resources are available forunassociated STAs. In other aspects, the first and second special valuesmay other suitable integer values.

In some implementations, the first AP may be associated with atransmitted BSSID (Tx BSSID), and each of the other APs is associatedwith a corresponding non-transmitted BSSID (non-Tx BSSID). When atrigger frame is transmitted from the Tx BSSID (such as from the firstAP operating as the Tx AP), the transmitter address (TA) of the triggerframe is set to the MAC address of the Tx BSSID. Referring also to theexample operation 1110 of FIG. 11B, the first AP may allocate one ormore random resource units (RUs) for use by stations associated with aselected one of the non-Tx BSSIDs by setting an AID value to a BSSIDindex of the selected non-Tx BSSID (1111). In addition, or in thealternative, the first AP may allocate one or more random RUs for use bystations associated with the Tx BSSID by setting an AID value to zero(1112). In addition, or in the alternative, the first AP may allocateone or more random RUs for use by all unassociated stations by settingan AID value to 2045 (1113).

In other implementations, the first AP may be associated with a non-TxBSSID. When a trigger frame is transmitted from a non-Tx BSSID (such asfrom the first AP operating as a non-Tx AP), the transmitter address(TA) of the trigger frame is set to the MAC address of the non-Tx BSSID.Referring also to the example operation 1120 of FIG. 11C, the first APmay allocate one or more random RUs for use by stations associated withthe non-Tx BSSID by setting an AID value to zero (1121). In addition, orin the alternative, the first AP may allocate one or more random RUs foruse by all unassociated stations by setting an AID value to 2045 (1122).

The first AP may transmit a trigger frame containing the number of AIDvalues to the stations belonging to the multiple BSSID set (1102). Insome aspects, the trigger frame may contain the AID value set to theBSSID index of the selected non-Tx BSSID, for example, to allocate theone or more random RUs for use by stations associated with the selectednon-Tx BSSID for UL transmissions. In other aspects, the trigger framemay contain the AID value set to zero, for example, to allocate the oneor more random RUs for use by stations associated with the Tx BSSID forUL transmissions. In other aspects, the trigger frame may contain theAID value set to 2045, for example, to allocate the one or more randomRUs for use by all of the unassociated stations for UL transmissions.

The first AP may transmit a management frame including the partialvirtual bitmap containing the group AID mapping (1103). In someimplementations, the partial virtual bitmap indicates at least one of apresence of group address traffic for the Tx BSSID, a presence of groupaddress traffic for one or more of the non-Tx BSSIDs, and a presence ofqueued DL data for unassociated stations. The management frame may alsocontain a multiple BSSID element including an indication that the firstAP operates the multiple BSSID set and is associated with the Tx BSSID.The multiple BSSID element may also include BSSID values assigned to theTx BSSID and the non-Tx BSSIDs.

In some implementations, management frame may announce multiple BSSIDcapabilities of the first AP. The management frame also may include themultiple BSSID capabilities of the APs associated with the non-TxBSSSIDs. In some aspects, the management frame may include a randomaccess parameter (RAPS) element indicating orthogonal frequency-divisionmultiple access (OFDMA) contention window values for stations associatedwith the first AP (1104). In some aspects, the management frame alsoincludes, for each of the other APs, a corresponding RAPS elementindicating OFDMA contention window values for stations associated withthe respective one of the other APs (1105).

FIG. 12 shows an illustrative flow chart depicting another exampleoperation 1200 for allocating wireless resources of a multiple basicservice set identifier (BSSID) set to a number of stations (STAs). TheBSSID set may include a first basic service set (BSS) associated with afirst access point (AP) and a number of other BSSs each associated witha corresponding one of a number of other APs. In some implementations,the first AP may operate the BSSID set and may perform the exampleoperation 1200. In some aspects, the first AP may be the AP 110 of FIG.1A, the AP of FIG. 1B, or the AP 400 of FIG. 4. In other aspects, thefirst AP may be another suitable AP.

The first AP may transmit a beacon frame including a partial virtualbitmap indicating a presence or absence of queued downlink (DL) data foreach of a plurality of stations, irrespective of the particular BSS towhich any of the stations belong (1201). In some implementations, afirst bit of the partial virtual bitmap indicates the presence orabsence of DL data for stations associated with the first AP, each of anumber of second bits of the partial virtual bitmap indicates thepresence or absence of DL data for stations associated with acorresponding one of the number of other APs, and a third bit of thepartial virtual bitmap indicates the presence or absence of DL data forstations not associated with any of the APs.

The beacon frame may include a multiple BSSID element indicating thatthe first AP operates the multiple BSSID set and is associated with thefirst BSS. In some aspects, the multiple BSSID element may indicate aBSSID index for the first AP and indicates a BSSID index for each of thenumber of other APs. The beacon frame may also indicate multiple BSSIDcapabilities of the first AP and indicates multiple BSSID capabilitiesof each of the number of other APs. In addition, or in the alternative,the beacon frame may include a random access parameter (RAPS) elementindicating orthogonal frequency-division multiple access (OFDMA)contention window values for stations associated with the first AP. Insome aspects, the beacon frame may also include, for each of the numberof other APs, a corresponding RAPS element indicating OFDMA contentionwindow values for stations associated with the respective one of theother APs.

The first AP may allocate a first number of random resource units (RUs)for use by stations associated with the first BSS (1202), and mayallocate a second number of RUs for use by stations associated with oneor more of the other BSSs (1203).

The first AP may transmit a trigger frame indicating the allocation ofthe first number of RUs for use by stations associated with the firstBSS and the allocation of the second number of RUs for use by stationsassociated with the one or more other BSSs (1204).

The first AP may allocate a dedicated RU to a selected stationassociated with the first AP, and the trigger frame may indicate theallocation of the dedicated RU to the selected station (1205). In thismanner, a single trigger frame may allocate dedicated RUs to one or moreselected stations associated with the first AP while also allocatingrandom RUs to a number of stations, irrespective of whether the stationsare associated with the AP that transmitted the trigger frame.

FIG. 13 shows an illustrative flow chart depicting an example operation1300 for operating a wireless station in a multiple basic service setidentifier (BSSID) set. The multiple BSSID set may include a transmittedBSSID (Tx BSSID) and a number of non-transmitted BSSIDs (non-Tx BSSIDs).In some implementations, the wireless station may be one of the stationsSTA1-STA4 of FIG. 1A, one of the stations STA1-STA99 of FIG. 1B, or theSTA 300 of FIG. 3. In other aspects, the wireless station may be anothersuitable wireless device.

The wireless station receives a management frame including a partialvirtual bitmap and a number of random access parameter set (RAPS)elements (1302). Each RAPS element may indicate orthogonalfrequency-division multiple access (OFDMA) contention window values forstations associated with a corresponding one of the BSSIDs. In someaspects, each RAPS element may include an OFDMA Contention Window (OCW)range field that stores a minimum OCW value and a maximum OCW value fora corresponding BSSID. During random channel access operations, each ofthe receiving stations may select an OBO count value that is between theminimum OCW value and the maximum OCW value indicated in thecorresponding RAPS element.

In some implementations, the management frame is transmitted by the TxBSSID and may include a RAPS element for the Tx BSSID. If the wirelessstation belongs to a respective one of the non-Tx BSSIDs and has notreceived a RAPS element corresponding to the respective non-Tx BSSID,the wireless station may inherit the RAPS element of the Tx BSSID basedon the absence of any RAPS element corresponding to the respectivenon-Tx BSSID (1302A).

In other implementations, the wireless station may belong to respectiveone of the non-Tx BSSIDs that does not allocate random RUs to itsassociated stations. The respective non-Tx BSSID may indicate that itdoes not allocate random RUs to its associated stations in acorresponding RAPS element. In some implementations, the wirelessstation may receive a RAPS element indicating that the respective non-TxBSSID does not allocate random RUs to its associated stations (1302B).In some aspects, the RAPS element may include a special value or adedicated field explicitly indicating that the respective non-Tx BSSIDdoes not allocate random RUs. Wireless stations receiving a RAPS elementthat includes the special value or the dedicated field may determinethat the non-Tx BSSID corresponding to the received RAPS element doesnot allocate random RUs to wireless stations.

In other aspects, the RAPS element may include a length field set to oneor may be missing an OFDMA contention window (OCW) range field toindicate that the respective non-Tx BSSID does not allocate random RUs.Wireless stations receiving a RAPS element that includes a length fieldset to one or that does not include an OFDMA contention window (OCW)range field may determine that the non-Tx BSSID corresponding to thereceived RAPS element does not allocate random RUs to wireless stations.

The wireless station may determine a presence of downlink (DL) data inone or more of the BSSIDs based on the partial virtual bitmap (1304). Insome implementations, the partial virtual bitmap may allow an AP toindicate the presence of group address traffic for the Tx BSSID, toindicate the presence of group address traffic for each of the non-TxBSSIDs, and to indicate the presence of queued downlink (DL) data forSTAs associated with any of the different BSSs belonging to the multipleBSSID set 130 (irrespective of whether the STAs are associated with theTx BSSID or one of the non-Tx BSSIDs) using a single traffic indicationmap (TIM) element, as described above.

The wireless station may receive a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in the partial virtual bitmap of a traffic indication map(TIM) element (1306). In some implementations, the trigger frame isreceived from an access point (AP) corresponding to the Tx BSSID andincludes a transmitter address (TA) set to a MAC address of the TxBSSID. In other implementations, the trigger frame is received from anaccess point (AP) corresponding to a respective one of the non-Tx BSSIDsand includes a transmitter address (TA) set to a MAC address of therespective non-Tx BSSID.

The wireless station may determine whether the trigger frame allocatesone or more random resource units (RUs) for use by the station based onone or more of the AID values contained in the trigger frame (1308).When the trigger frame is received from an AP corresponding to the TxBSSID and the wireless station is associated with the Tx BSSID, thewireless station may determine whether the trigger frame allocates oneor more random RUs for use by the station by identifying, in the triggerframe, an AID value set to zero. When the trigger frame is received froman AP corresponding to the Tx BSSID and the wireless station isassociated with respective one of the non-Tx BSSIDs, the wirelessstation may determine whether the trigger frame allocates one or morerandom RUs for use by the station by identifying, in the trigger frame,an AID value set to a BSSID index of the respective non-Tx BSSID. Whenthe wireless station is not associated with any of the BSSIDs, thewireless station may determine whether the trigger frame allocates oneor more random RUs for use by the station by identifying, in the triggerframe, an AID value set to 2045.

When the trigger frame is received from an AP corresponding to arespective one of the non-Tx BSSIDs and the station wireless station isassociated with the respective non-Tx BSSID, the wireless station maydetermine whether the trigger frame allocates one or more random RUs foruse by the station by identifying, in the trigger frame, an AID valueset to zero. When the trigger frame is received from an AP correspondingto a respective one of the non-Tx BSSIDs and the wireless station is notassociated with any of the BSSIDs, the wireless station may determinewhether the trigger frame allocates one or more random RUs for use bythe station by identifying, in the trigger frame, an AID value set to2045.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover: a, b, c,a-b, a-c, b-c, and a-b-c.

The various illustrative logics, logical blocks, modules, circuits andalgorithm processes described in connection with the implementationsdisclosed herein may be implemented as electronic hardware, computersoftware, or combinations of both. The interchangeability of hardwareand software has been described generally, in terms of functionality,and illustrated in the various illustrative components, blocks, modules,circuits and processes described above. Whether such functionality isimplemented in hardware or software depends upon the particularapplication and design constraints imposed on the overall system.

The hardware and data processing apparatus used to implement the variousillustrative logics, logical blocks, modules and circuits described inconnection with the aspects disclosed herein may be implemented orperformed with a general purpose single- or multi-chip processor, adigital signal processor (DSP), an application specific integratedcircuit (ASIC), a field programmable gate array (FPGA) or otherprogrammable logic device, discrete gate or transistor logic, discretehardware components, or any combination thereof designed to perform thefunctions described herein. A general purpose processor may be amicroprocessor, or, any conventional processor, controller,microcontroller, or state machine. A processor also may be implementedas a combination of computing devices such as, for example, acombination of a DSP and a microprocessor, a plurality ofmicroprocessors, one or more microprocessors in conjunction with a DSPcore, or any other such configuration. In some implementations,particular processes and methods may be performed by circuitry that isspecific to a given function.

In one or more aspects, the functions described may be implemented inhardware, digital electronic circuitry, computer software, firmware,including the structures disclosed in this specification and theirstructural equivalents thereof, or in any combination thereof.Implementations of the subject matter described in this specificationalso can be implemented as one or more computer programs, i.e., one ormore modules of computer program instructions, encoded on a computerstorage media for execution by, or to control the operation of, dataprocessing apparatus.

If implemented in software, the functions may be stored on ortransmitted over as one or more instructions or code on acomputer-readable medium. The processes of a method or algorithmdisclosed herein may be implemented in a processor-executable softwaremodule which may reside on a computer-readable medium. Computer-readablemedia includes both computer storage media and communication mediaincluding any medium that can be enabled to transfer a computer programfrom one place to another. A storage media may be any available mediathat may be accessed by a computer. By way of example, and notlimitation, such computer-readable media may include RAM, ROM, EEPROM,CD-ROM or other optical disk storage, magnetic disk storage or othermagnetic storage devices, or any other medium that may be used to storedesired program code in the form of instructions or data structures andthat may be accessed by a computer. Also, any connection can be properlytermed a computer-readable medium. Disk and disc, as used herein,includes compact disc (CD), laser disc, optical disc, digital versatiledisc (DVD), floppy disk, and blu-ray disc where disks usually reproducedata magnetically, while discs reproduce data optically with lasers.Combinations of the above should also be included within the scope ofcomputer-readable media. Additionally, the operations of a method oralgorithm may reside as one or any combination or set of codes andinstructions on a machine readable medium and computer-readable medium,which may be incorporated into a computer program product.

Various modifications to the implementations described in thisdisclosure may be readily apparent to those skilled in the art, and thegeneric principles defined herein may be applied to otherimplementations without departing from the spirit or scope of thisdisclosure. Thus, the claims are not intended to be limited to theimplementations shown herein, but are to be accorded the widest scopeconsistent with this disclosure, the principles and the novel featuresdisclosed herein.

What is claimed is:
 1. A method of operating a wireless station in amultiple basic service set identifier (BSSID) set including atransmitted BSSID (Tx BSSID) and a number of non-transmitted BSSIDs(non-Tx BSSIDs), the method performed by the wireless station andcomprising: receiving a trigger frame containing a number of associationidentifier (AID) values based on a group AID mapping contained in apartial virtual bitmap of a traffic indication map (TIM) element; anddetermining whether the trigger frame allocates one or more randomresource units (RUs) for use by the station based on one or more of theAID values contained in the trigger frame.
 2. The method of claim 1,wherein the one or more random RUs are allocated for at least one of agroup of stations, a specific BSSID, a group of BSSIDs, and all of thestations belonging to the multiple BSSID set.
 3. The method of claim 1,wherein one of the AID values contained in the trigger frame is set to aspecial value that allocates one or more random RUs to all stationsbelonging to the multiple BSSID set.
 4. The method of claim 1, whereinthe trigger frame is received from an access point (AP) corresponding tothe Tx BSSID and includes a transmitter address (TA) set to a MACaddress of the Tx BSSID.
 5. The method of claim 4, wherein the stationis associated with the Tx BSSID, and the determining comprises:identifying, in the trigger frame, an AID value set to zero.
 6. Themethod of claim 4, wherein the station is associated with a respectiveone of the non-Tx BSSIDs, and the determining comprises: identifying, inthe trigger frame, an AID value set to a BSSID index of the respectivenon-Tx BSSID.
 7. The method of claim 4, wherein the station is notassociated with any of the BSSIDs, and the determining comprises:identifying, in the trigger frame, an AID value set to
 2045. 8. Themethod of claim 1, wherein the trigger frame is received from an accesspoint (AP) corresponding to a respective one of the non-Tx BSSIDs andincludes a transmitter address (TA) set to a MAC address of therespective non-Tx BSSID.
 9. The method of claim 8, wherein the stationis associated with the respective non-Tx BSSID, and the determiningcomprises: identifying, in the trigger frame, an AID value set to zero.10. The method of claim 8, wherein the station is not associated withany of the BSSIDs, and the determining comprises: identifying, in thetrigger frame, an AID value set to
 2045. 11. The method of claim 1,further comprising: receiving a management frame including the partialvirtual bitmap; and determining a presence of downlink (DL) data in oneor more of the BSSIDs based on the partial virtual bitmap.
 12. Themethod of claim 11, wherein the management frame is received from anaccess point (AP) associated with the Tx BSSID, the management framecomprising: an indication that the AP operates the multiple BSSID setand is associated with the Tx BSSID; and a random access parameter set(RAPS) element indicating orthogonal frequency-division multiple access(OFDMA) contention window values for stations associated with the TxBSSID.
 13. The method of claim 12, wherein the station is associatedwith a respective non-Tx BSSID, and the method further comprises:inheriting the RAPS element from the Tx BSSID based on an absence of anyRAPS element corresponding to the respective non-Tx BSSID.
 14. Themethod of claim 12, wherein the station is associated with a respectivenon-Tx BSSID, and the method further comprises: receiving a RAPS elementindicating that the respective non-Tx BSSID does not allocate randomRUs.
 15. The method of claim 14, wherein the respective RAPS elementcomprises a length field set to one or is missing an OFDMA contentionwindow (OCW) range field.
 16. A wireless station belonging to a multiplebasic service set identifier (BSSID) set including a transmitted BSSID(Tx BSSID) and a number of non-transmitted BSSIDs (non-Tx BSSIDs), thewireless station comprising: one or more processors; and a memorystoring instructions that, when executed by the one or more processors,cause the wireless station to: receive a trigger frame containing anumber of association identifier (AID) values based on a group AIDmapping contained in a partial virtual bitmap of a traffic indicationmap (TIM) element; and determine whether the trigger frame allocates oneor more random resource units (RUs) for use by the station based on oneor more of the AID values contained in the trigger frame.
 17. Thewireless station of claim 16, wherein the trigger frame is received froman access point (AP) corresponding to the Tx BSSID and includes atransmitter address (TA) set to a MAC address of the Tx BSSID.
 18. Thewireless station of claim 17, wherein the wireless station is associatedwith the Tx BSSID, and execution of the instructions for the determiningcauses the wireless station to: identify, in the trigger frame, an AIDvalue set to zero.
 19. The wireless station of claim 17, wherein thewireless station is associated with a respective one of the non-TxBSSIDs, and execution of the instructions for the determining causes thewireless station to: identify, in the trigger frame, an AID value set toa BSSID index of the respective non-Tx BSSID.
 20. The wireless stationof claim 17, wherein the wireless station is not associated with any ofthe BSSIDs, and execution of the instructions for the determining causesthe wireless station to: identify, in the trigger frame, an AID valueset to
 2045. 21. The wireless station of claim 16, wherein the triggerframe is received from an access point (AP) corresponding to arespective one of the non-Tx BSSIDs and includes a transmitter address(TA) set to a MAC address of the respective non-Tx BSSID.
 22. Thewireless station of claim 21, wherein the station wireless station isassociated with the respective non-Tx BSSID, and execution of theinstructions for the determining causes the wireless station to:identify, in the trigger frame, an AID value set to zero.
 23. Thewireless station of claim 21, wherein the wireless station is notassociated with any of the BSSIDs, and execution of the instructions forthe determining causes the wireless station to: identify, in the triggerframe, an AID value set to
 2045. 24. The wireless station of claim 16,wherein execution of the instructions further causes the wirelessstation to: receive a management frame including the partial virtualbitmap; and determine a presence of downlink (DL) data in one or more ofthe BSSIDs based on the partial virtual bitmap.
 25. The wireless stationof claim 24, wherein the management frame is received from an accesspoint (AP) associated with the Tx BSSID, the management framecomprising: an indication that the AP operates the multiple BSSID setand is associated with the Tx BSSID; and a random access parameter set(RAPS) element indicating orthogonal frequency-division multiple access(OFDMA) contention window values for stations associated with the TxBSSID.
 26. The wireless station of claim 24, wherein the station isassociated with a respective non-Tx BSSID, and execution of theinstructions further causes the wireless station to: inherit the RAPSelement from the Tx BSSID based on an absence of any RAPS elementcorresponding to the respective non-Tx BSSID.
 27. The wireless stationof claim 24, wherein the station is associated with a respective non-TxBSSID, and execution of the instructions further causes the wirelessstation to: receive a RAPS element indicating that the respective non-TxBSSID does not allocate random RUs.
 28. The wireless station of claim27, wherein the respective RAPS element comprises a length field set toone or is missing an OFDMA contention window (OCW) range field.
 29. Anon-transitory computer-readable medium storing instructions that, whenexecuted by one or more processors of a wireless station belonging to amultiple basic service set identifier (BSSID) set including atransmitted BSSID (Tx BSSID) and a number of non-transmitted BSSIDs(non-Tx BSSIDs), cause the wireless station to perform a number ofoperations comprising: receiving a trigger frame containing a number ofassociation identifier (AID) values based on a group AID mappingcontained in a partial virtual bitmap of a traffic indication map (TIM)element; and determining whether the trigger frame allocates one or morerandom resource units (RUs) for use by the station based on one or moreof the AID values contained in the trigger frame.
 30. A wireless stationbelonging to a multiple basic service set identifier (BSSID) setincluding a transmitted BSSID (Tx BSSID) and a number of non-transmittedBSSIDs (non-Tx BSSIDs), the wireless station comprising: means forreceiving a trigger frame containing a number of association identifier(AID) values based on a group AID mapping contained in a partial virtualbitmap of a traffic indication map (TIM) element; and means fordetermining whether the trigger frame allocates one or more randomresource units (RUs) for use by the station based on one or more of theAID values contained in the trigger frame.